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EC-Lab software Techniques and Applications manual

1. Mrez Mn s fixes a maximum time tp to stay in open circuit mode or until dEwe dt lt dEp dt mV h gives to the user the possibility to shorten the open circuit period when the decay of the potential is lower than a given value Record Ewe every dEr mV and at least every dtg sS allows the user to record the working electrode potential with a given potential resolution whenever the change in the working electrode potential is gt dEr or and at least every dtr time interval 192 Techniques and Applications Manual Note the conditional test if tz 0 which bypasses the open circuit period e Third step test on the final open circuit potential test Ewe gt lt E V The test is performed with the conditional value gt if the open circuit period just before the test occurs after a charge I gt 0 and with the conditional value lt after a discharge I lt 0 If the condition is not fulfilled the above 3 steps will be repeated until the working electrode potential reaches the final open circuit condition Eye 2 E after a charge or Ewe lt E after a discharge Note the user is allowed to bypass this test by entering p pass instead of a voltage value e Fourth step conditional test which proposes to go to the next sequence or to loop on a previous sequence Ns Ns lt Ns lf n is set to 0 then the technique executes the next sequence lf the user wants
2. fA h A h pC kKC and dt S lt I gt every dts S 70 Techniques and Applications Manual You can record either an instantaneous current value or an averaged current value lt I gt The recording conditions during the potential step depend on the chosen current variable For the instantaneous current the recording values can be entered simultaneously The first condition reached determines the recording A zero value disables the recording for each criterion For the averaged current the user defines the time for the average calculation In that case the data points are recorded in the channel board memory every 200 us for the VMP2 VMP3 MPG2 VSP SP series and the BiStat and 20 ms for the VMP and the MPG enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range and Bandwidth fixes the current range and bandwidth for this experiment 2 4 2 3 Potentiodynamic Mode 2 iE 0 000 pass Pass Do0 mah Bo 5 aE 4 4 ij 4 4 Go back to sequence Ne lo SITS AATE jaca for My lo time s Aleve A eer A dE dt 100 py 5 0 ms JEM 500 ps ae Fig 62 Modular Potentio potentiodynamic detailed diagram 71 Techniques and Applications Manual Scan Eye with dE dt mV s defines the pote
3. OCV potential Eo controlled potential Eet 33 Techniques and Applications Manual measured potential Emeas for a te duration Sets te large enough to wait for the cell current stabilization if the applied potential is different from the open circuit potential During this period no impedance measurement is done Note if another experiment is defined before then it is possible to define the initial potential as a function of Ear and Emeas previous potential controlled and previous potential measured respectively If there is no experiment before it is not possible to use Eg and Emeas O Record every dl nA UA mA A and dt sS offers the possibility to record Ewe and I during the DC period before the AC simulation with two conditions on the current variation dl and or on time variation e Impedance scan Scan from fi MHz kHz Hz mHz yHz to f MHz kHz Hz mHz yHz defines the initial fi and final f frequencies of the scan To have the first measured point more rapidly it is recommended to scan from the highest frequencies to the lowest ones but it is possible to reverse the frequencies scan order with Ng points per decade in Logarithm spacing N nannan points from fi to ff in Linear spacing defines the frequencies distribution between the scan bounds f and f It is possible to select the number of points per decade Ng or the total number of points N in line
4. p est U Rest Potential Sequence Test Ewe vs EL irit He Nest Sequence or go nc times to sequence Ns End Fig 84 General diagram of the GCPL application mio a3 Oe om of 90 Techniques and Applications Manual 0 000 0 Th i T co a a a a oo ia co D D D 4 3 4 l mAh T in 4 4 120 000 0 3 Ewe lt EL Ra goto 7 4 Go back ta seq Ne fr FGI aa AAY ARAR for My lo time ls AAV vases wae e 0e Fig 85 Detailed diagram of one GCPL sequence In the battery applications the current values panel displays additional information Q Qo and x Xo are the total charge and the normalized charge since the beginning of the experiment respectively N is the current sequence number in case of a technique using several sequences It corresponds to the line number in the associated table The first sequence number is 0 Nci Nes are the current values of the 5 loop counters 91 Techniques and Applications Manual 3 1 2 1 Description of a galvanostatic sequence See Fig 85 e First step galvanostatic period that can be followed by a potentiostatic period 1 Galvanostatic period Set I to Is pA A vs lt None gt Ictrl Imeas for at most t h mn S fixes the current value in absolute versus the previous controlled current previous sequence or versus the previous measured current and the maximum du
5. 138 Techniques and Applications Manual Set Ewe to Ecorr Apply a sinusoidal potential with frequency Fe 0 100 Hz amplitude Wa i ng ry ws Ecom Repeat ng 20 timels Hecond ever dt 0 500 0 amp ERange 2 2 Arena Fa Range 100 pA Bandwidth F duration 210 000 s Fig 125 Detailed diagram of the Constant Amplitude Sinusoidal microPolarization technique Description e Apply a sinusoidal potential with frequency f kHz Hz mHz uHz sets the frequency of the modulation applied to the cell The maximum frequency is 500 Hz Amplitude Va mV vs Ecorr Sets the amplitude the sinus Repeat n time s allows repeating sinusoidal period Repetition leads to optimized results It is recommend to perform 20 cycles at least Record every dt sS sets the sampling rate of the measurement enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment lrange Bandwidth Sets the current range and the bandwidth for the whole experiment Note it is recommend to adjust a fix current range in order to get constant sampling rate 3 3 6 GC Generalized Corrosion The generalized corrosion technique is applied for general corrosion Sometimes called uniform corrosion study For this corrosion anodic dissolution is uniformly distribu
6. 2 mV h Piatt Fig 101 Power vs energy plot for a Li ion cell 1 35 A h P 8 W A process called Constant Power technique summary has been especially designed for Ragone plot representation To use this data process click on process in the graphic 112 Techniques and Applications Manual window or choose Process data Constant Power technique summary in the File menu Then the following processing window will be displayed Constant Power protocol summary mtm Raw File CAE C Lab DatasS amples CPW _RAGONE mpr times FPA Energy h O Qol m h Ewe initial l m initial Ewe final i m final 1185 7890 5 0006 2612 2 T6015 4 063 9 1 624 7 3 001 3 2 665 8 2602 6217 3 9986 3 425 7 1 007 2 3 646 1 596 6 3 001 1 332 3526 4155 20021 3 642 6 1 OFF 3 293 5 477 93 3 001 4 B67 06 4686 4659 1 0007 af 54 4 1 113 6 3 171 225 45 3 002 1 333 35 5565 7811 0 497 59 3 820 9 1 135 5 3 097 6 56 968 3 001 4 165 58 6457 3199 0 250 27 3 662 8 1 149 4 3 056 1 18 914 3 001 7 53 376 TPl4 6663 0 124 41 3 893 7 1 159 6 3 036 7 17 24 3 002 2 41 44 DONE Process Copy Close Fig 102 CPW process window This process window is made of a table containing the characteristic variables of each power step such as the time the energy and charge of the end of the step the working electrode potential and the current that crossed the cell at the beginning and the end of the step The Copy tab allows the user to paste the valu
7. Moving the sliding index acts on the potential value in the given limits You can also change the potential value in the intermediate box It is applied when you hit enter The cell is turned off by using the Stop button You can always read the applied potential and the current running in the cell in the potential and current panels on the right 2 5 2 Current Manual Control This menu proposes the same features as the Potential Manual Control by replacing the potential control by the current control Therefore report to the Potential Manual Control section previously described for more details 79 Techniques and Applications Manual 2 6 Ohmic Drop Determination The ohmic drop is defined by the solution resistance between the working electrode and the reference electrode It is a critical parameter that can be significant when experiments are made in nonaqueous media It may lead to severe distortion of the voltammetric response The best way to determine the uncompensated resistance R is to perform an impedance measurement at high frequencies before to run other experiments 2 6 1 MIR manual IR compensation lf the user knows the value of Ru he should set the value in the box and define the compensation percentage The value of compensate R can be used for IR compensation in linked techniques set Ry compensate at 85 pa Fig 74 MIR diagram 2 6 2 ZIR IR compensation with EIS The ZIR technique offers the pos
8. Note 1 For the 1 sequence sweep Ns 0 the galvanostatic block is ignored This allows the user to run a 1 open circuit period before starting a charge or discharge sequence Note 2 If the AQwy limit is reached the Ewe vs E test is ignored and the next sequence is executed Note 3 The choice of the operating current range which is usually done in the I Range menu of the Parameter settings window can also be obtained by double clicking on any cell of the corresponding column in the table associated to the detailed diagram window 3 1 2 2 Application The following figure shows the result of a GCPL experiment obtained with a Li ion battery 10 A h in an intermittent charge discharge cycling GITT mode Ewe ve time 1TS 53 9 sCPL_3 12b 4 impri lt i gt ve time 1S 5379 GCPL 3 126 4 mpr a O00 2 500 2 OOD 7 1 500 1 000 500 1 000 Ewe V Pu f gt 1 500 2 000 2 500 3 O00 3 i i i i i i l ji 3 500 4000 4 500 5 000 1 000 000 1 050 000 time s Fig 87 Example of GCPL experiment obtained with a Li ion battery 10 A h 94 Techniques and Applications Manual 3 1 2 3 GCPL Data processing 3 1 2 3 1 Compacting process for the apparent resistance determination Selecting Keep only values at the end of every open circuit period on period compresses the data resulting from the raw data file by keeping only one point for the w
9. Varables Representation times s control mA E stack EVs E27 E 3s E 4s dager Pia lt gt rn Q Qo mad h Ht Z Same selection for all files 3 Hide Additional Variables V keep previous axes process keep previous zoom Cancel Fig 180 PEIS left and GCPL right selection window for a stack experiment One can see that for stack experiment a Slave selection is available to display all the slave data points in the same graphic window For EIS experiments Nyquist and Bode plots are available both for the whole stack and for the elements 203 Techniques and Applications Manual Summary of the available techniques and applications in EC Lab TECHNIQUES VMP HCP 1005 Voltamperometric techniques Pulsed techniques DPV x x x x x x x SWV x x x x x x x DNPV x x x x x x x NPV x x x x x x x RNPV x x x x x x x DPA x x x x x x x EIS techniques Technique builder Wait Loop EEEE GEORG VELEIRO Jalie CMC PMC Ohmic Drop determination Battery testing Trigger In Trigger Out PCGA x x x x x x x GCPL x x x x x x x GCPL2 x x x x x x x GCPL3 x x x x x x x GCPL4 x x x x x x x GCPL5 x x x x x x x CLD x x x x x x x CPW x x x x x x x 204 Techniques and Applications Manual Custom applications Special applications 205 Techniques and Applications Manual List of abbreviations used in EC Lab
10. nA uUA mA A 2 Techniques and Applications Manual offers the possibility to record with two conditions on the current variation dl and or on time variation enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment range bandwidth enables the user to select the current range and the bandwidth damping factor of the potentiostat regulation Note this technique includes sequences to link sines with different amplitude for example 2 1 9 Alternating Current Voltammetry ACV Alternating Current Voltammetry ACV is assimilated to a faradaic impedance technique On this technique a sinusoidal voltage of small amplitude A with a constant frequency fs is Superimposed on a linear ramp between two vertex potentials E E2 The potential sweep E is defined as follow E t E t Asin 2 z f t Typically the linear ramp varies on a long time scale compared to the superimposed AC variation Like the pulsed techniques ACV discriminates the faradaic current from the capacitive one Consequently ACV can be used for analytical purpose Moreover this technique can also be used for investigating electrochemical mechanism for instance superimposition of forward and backward scan characterize a reversible redox system Begin Set Initial Potential to E Ewe E1 A i dE
11. nee Run bec Tec Loop Fig 174 Linked experiment current values In our example the output files will be pappe a a Har sap ETTE Ste He gente em eae at te ii ont Ewe V Fig 175 Linked experiment results Notes e The ZRA MUIC techniques and the manual controls cannot be linked 197 Techniques and Applications Manual e The Polarization Resistance process calculation can be performed on the technique linker loops separately Linked experiments settings can be saved with Experiment Save As or on the right click menu with Save experiment and reloaded with Experiment Load settings or with the right click Load settings Linked experiments files are text files with the mps extension like the standard settings files 198 Techniques and Applications Manual Stack experiments EC Lab software has the capability to perform measurements DC or AC on a stack of energy devices or other electrochemical system In this kind of devices we can mention Lithium battery stacks solar cells fuel cell stacks Using our accessory SAM 50 which is a voltage sense adapter from 50 V to 10 V in addition with a 50 V load box we can easily study stacks of fuel cells up to 50 V In this case one channel is used as a master channel to control the whole stack and the other are managed by the master and used to do measurements on each element of the stack In series the current crossing each element is the same
12. rea Fay Fig 67 Temparature control O Set temperature to Rpm on External Thermostat one can set a temperature and configure the temperature recording using the External thermostat link menu Config External Devices see the Critical Pitting Temperature for the VMP only Record every dE mV dl pA A and dt s chooses one or several optional recording conditions enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Caution The TC technique has a parameters table in the parameters settings window which can be related to the sequences selection The user can link several TC sequences N 0 to n These sequences are linked differently from the other techniques In other standard technique one sequence is executed directly after the other For the TC technique each sequence corresponds to a loop of a linked technique see after Therefore only one sequence of the wait technique is executed at each loop of the linked experiment The sequences are considered successively at each loop This allows the user to increase temperature values at each sequence loop If more experiment loops than the number of sequences are set in the TC experiment table then the TC technique is restarted from the beginning 2 4 6 Rotating Disk Electrode Control RDEC The Rotating D
13. runs the reverse sweep towards a 2 limit potential The vertex potential value can be set in absolute vs Ref the reference electrode potential or according to the previous open circuit potential E or to the initial potential Ej e Repeat option for cycling Repeat n times repeats the whole sequence n time s Note that the number of repeat does not count the first sequence if Nne 0 then the sequence will be done 1 time ne 1 the sequence will be done 2 times Nn 2 the sequence will be 3 times Measure lt I gt over the last of the step duration selects the end part of the potential step from 1 to 100 for the current average lt I gt calculation to possibly exclude the first points where the current may be disturbed by the step establishment Note that the current average lt I gt is recorded at the end of the potential step in the data file Record lt l gt averaged over N voltage step s averages N current values on N potential steps in order to reduce the data file size and smooth the trace The potential step between two recording points is indicated between brackets Once selected an estimation of the number of points per cycle is displayed in the diagram enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment range ban
14. 4 4 et 4 pass 5O 3 IFEwe gt EL pass WW then go ta 1 Go back to seq MN D GG ant facta for nip D time s TAVAS wave Fig 170 Detailed diagram of one SGCPL sequence e First step galvanostatic period that can be followed by a potentiostatic period T Techniques and Applications Manual 1 Galvanostatic period Set I to Is pA A vs lt None gt Ictrl Imeas for at most t h mn S fixes the current value in absolute versus the previous controlled current previous sequence or versus the previous measured current and the maximum duration of the imposed current period The sign of the current value is for a discharge and for a charge when the positive electrode of the cell is connected to the Working electrode cable red enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Or until IdE dtl lt dEm dt mV h with I Range and Bandwidth gives to the user the possibility to shorten the period when the decay of the potential is lower than a given value and allow the user to fixe the current range and the bandwidth for this experiment Record Ewe every dE mV and at least every dt s allows the user to record the working electrode potential with a given poten
15. 55 Techniques and Applications Manual This technique is often used in polarography and by biologists to define the most appropriate potential for the electrochemical detection to a fixed potential with the DPA technique SetEwe to Ej 0200 Y vs Eos fort D hi mn pon ScanEwe from Ej to Ey 0600 WV vs Ref with pulses height PH 100 mv prepulse width PPyy 00 ms aa pulse width Pw 100 ms lt n step height SH coo mY step time ST 1000 ms average over the last i oo of each pule inaia DANE AG aah E Ranges 2y 23W a m Arena Aad Range 10 p Bandwidth m Fig 46 DNPV waveform Fig 45 DNPV detailed diagram Description e Initial potential Set Ewe to Ej V vs Ref Eoc Ectrl Emeas fort Leer mn S sets Ewe to the initial potential E This potential value can be set in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Eoc controlled potential Eer or measured potential Emeas Notice that only the last point of this period is recorded at the time O e Pulse waveform Scan Ewe from E to E V vs Ref Eoc Ei defines the vertex potential as E either in absolute vs Ref or versus Eg or Ei with pulses height Py mV Prepulse width PPy ms pulse width Py ms step height S4 mV step time S1 ms The scan increment is defined by a pseudo staircase made of steps wi
16. Potential sweep to E i with a sinusoid signal F Ei Reverse Potential Sweep to E Repeat mg times End Time T 1 cycle Fig 18 General diagram for Alternating Current Voltammetry This technique corresponds to usual cyclic voltammetry with a superimposition of a sinusoid The technique is composed of e astarting potential setting block a 1 potential sweep with a final limit E and a sinusoid superimposed a 2 potential sweep in the opposite direction with a final limit E gt option the possibility to repeat n times the 1 and the 2 potential sweeps Note that all the different sweeps have the same scan rate absolute value The detailed flow diagram on the following figure is made of three blocks Fig 17 28 Techniques and Applications Manual SetEwe to Ej 0 000 Wve Ref Scan Ewe with dEfdt A0000 mvs to vertes potential Eq 7 000 Vo va Re Add a sinusoidal signal to the potential scan with frequency F HoO 000 Hz l and amplitude A 0 000 mv _ Reverse scan to vertex Ep 0000 Vo ve Re Repeat ne o timefs Record ever d 0 001 Oo 8 and dl joo mA ERange 2 5 25 ha B Greaney Aa ed Range Auto Bandwidth z Reverse scan towards Ej Fig 19 Alternating Current Voltammetry detailed diagram e Starting potential Set Ewe to Ej V vs Ref Eoc Ectrl Emeas sets the starting potential in absolute vs Ref the reference electrode pot
17. Rei Repeat ng m timels Measure l gt over the last 50 Z of the step duration Record l gt averaged over H i voltage steps ERange 25 25 Areca Fedde Range Auto 7 Bandwidth 7 4 Endscanta Ef 0 000 YO y3 Eoc dE dt 100 000 mi s dEN 1 0 mi 4000 points per cycle Fig 15 Staircase Voltammetry detailed diagram e Starting potential Set Ewe to Ej V vs Ref Eoc Ectrl Emeas sets the starting potential in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Eoc controlled potential Eet or measured potential Emeas e First potential sweep with measurement and data recording conditions Scan Ewe with dE mV per dt s 300 uV 15 ms 24 Techniques and Applications Manual allows the user to set the potential step height in mV and the step duration in s Between brackets the scan rate is displayed according to the potential resolution defined by the user in the Advanced Settings window see the corresponding section in the EC Lab software manual for more details to vertex potential E V vs Ref Eoc Ei fixes the first vertex potential value in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Esc or to the initial potential Ej e Reverse scan Reverse scan towards vertex potential E V vs Ref Eoc Ei
18. The Potentio Electrochemical Impedance Spectroscopy Wait is a technique designed to do an impedance measurement at one frequency when the value of IZI has reached a defined value or after a time 0 000 E hoo oo Poo Z D D i i 4 mI E a ji 4 4 Fig 160 PEISW detailed diagram e Impedance scan Do PEIS measurement at Ewe V vs Ref Eoc Ectrl Emeas defines at which potential the measurement will be done fi nannan MHz kHz Hz mHz uHz defines at which frequency the measurement will be done with an amplitude V mV sets the sinus amplitude to Va Equivalence with Vrms is also given 177 Techniques and Applications Manual Note the following relationships between Va Vpp and Vams Va Vpp2 and Vams Vop 2 2 Wait for py period before each frequency measurement offers the possibility to add a delay before the measurement at each frequency This delay is defined as a part of the period Of course for low frequencies the delay may be long average N mesure s per frequency repeats Na measure s and average values for each frequency e Wait period Until IZI gt lt Zlim defines the duration of the wait as a function of a IZI value Zlim MQ kQ O mQO pO fixes the value of Zlim Or for tw h mn S Or as a function of the time o record data offers to the user the possibitlity to record the data before to reach the limit condition enables t
19. f ipa it Gaal E Fig 134 VMP TCU Connections The TCU can control a thermostat per channel or grouped channels controlled by the same temperature controller as shown below 151 Techniques and Applications Manual channel 1 channel ni measure of the T on Ueta TEU channel 1 channel n 4 20 mA Temperature control VIMP measure of Uwe Ua f control o dF I measure of T for regulation E N PT100 PT100 a S Ee Ap Soo Ee le j Cell 1 heating cooling liquid Thermostat Fig 135 Temperature control of several cells with a single thermostat 3 3 9 4 CPT Technique Before running any CPT experiment one must first calibrate the temperature controls Select Config External Device RDE in the EC Lab main menu to load the next window 152 Techniques and Applications Manual External Devices Thermostat RDE Configuration Channel Device Type Device Name Haake F6 C25 Haake P2 L25P Analog OUT Analog IN EA w with 400 ie 5 VW mas 100 L D VW min Manual Control Analog IN 2 TAC foo Activate Analog IN 3 Custom Varnables Fig 136 Temperature configuration for the Ministat First select the channel to configure In the Device Type select Thermostat and the Device Name in the list Either the standard supplied Ministat or an external thermostat can be selected For the Ministat the calibration parameters are fact
20. lt l gt on each potential step or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range and Bandwidth fixe the current range and bandwidth for this experiment The three modes of the Modular Potentio technique can be chained as sequences in the table in any order the user requires Each of the parameters can be modified in its box But parameters like Range or Bandwidth must keep the same value for all the sequences Note that the first sequence has the number N 0 Era aA o jo 0 00 1 0000 0 0 0 5000 0 0000 lt None gt 0 00 0 0000 0 000 1 000 0 0000 0 0 0 0000 0 0000 lt None gt 0 00 30 0000 0 000 O 0 00 0 0000 0 0 0 0000 0 0000 lt None gt 000 0 0000 20 000 3 Bao Hones hlano Fig 63 Modular Potentio table Note in this technique the first and last data points of each potential steps are not recorded automatically 2 4 3 Triggers Selecting the triggers option allows the user to insert a trigger command before or after a technique The procedure is the same as for linked techniques Two options are available 12 Techniques and Applications Manual trigger in and trigger out The next table summarizes th
21. related to intercalation electrodes e Report to the GCPL section for the description of the second third and fourth part of this technique In order to plot the apparent resistance variation versus logarithmic time the user must process the raw file after the experiment 102 Techniques and Applications Manual 3 1 6 2 GCPL5 Data processing see the data processing section in the EC Lab software manual Selecting Keep only values with geometric progression of time allows the user to keep data recorded with geometric time spacing in a processed file Once selected it calculates the ohmic drop Ri at different times recorded with geometric time spacing Then the name of the compacted processed file is filename channel_cR mpp in the case where Ri is the only processed variable Process Data Input File C NEC Lab DataSamples419650 cyclage 260504 GCP Load Processed File C EC Lab Data Samples 18850_cyclage_260504_GCF Change Variables To select from the input file To be added v mode diJ m h v osred 0 Holm h W error i control changes cycle number J Ne changes J RE Ohm v counter Inc Himes control mA Ewe dg m h v All All keep only values at the end of every v open circuit period on period Allow Reprocessing Cycles definition auto Export As Test Count half cycles Process Display Close Fig 93 GCPL 5 Process window Other processed values such as dQ I Q Qo
22. 1 0 1 0 2 0 3 O 4 05 Ewe V Fig 42 DPV measurement in a Fe II solution 2 3 2 SWV Square Wave Voltammetry Among the electroanalytical techniques the Square Wave Voltammetry SWV combines the background suppression the sensitivity of DPV and the diagnostic value of NPV The SWV is a large amplitude differential technique in which a waveform of a symmetrical Square wave with one pulse in the forward direction and one in the reverse superimposed on a base Staircase potential is applied to the working electrode The square wave is characterized by a pulse height Py and a pulse width Pw The pulse width can be expressed in terms of Square wave frequency f 1 2Pw The scan rate is v Py 2Pw The current is sampled twice during each square wave cycle once at the end of the forward pulse and once at the end of the reverse pulse The difference between the two measurements is plotted versus the base staircase potential The resulting peak shaped voltammogram is symmetrical around the half wave potential and the peak current is proportional to the concentration Excellent sensitivity accrues from the fact that the net current is larger than either the forward or reverse components since it is the difference between them 53 Techniques and Applications Manual SetEweto Ej 0500 Wo yg Ref forty 0 hi ma poog 3 ScanEwefromE to Ey jo500 vs Ref gt with pulses height PH 25 0 mv pulses width Pyy 50
23. 3 1 1 2 Description of the cell characteristics window for batteries E Channel 1 experiment lt no name gt technique Potentiodynamic Cycling with Galvanostatic Acceleration Tum to OCY between techniques lt lt Default sl Advanced Cell Description Record Settings Electrode material Ecen Cell Initial state Ewe E ce _ Characteristics _ Electrol te Pu Parameters i Analog IN 14 Settings Comments Analog IN 27 Record extemal devices on Analog INH send 1 PEGA Files Mass of active material 7000 000 mg aty i O00 WE Molecular weight of active material at x 0 90 930 g mol ren E Atomic weight of intercalated on 6 940 g mol ae Acquisition started at xo 0 950 Number of e transfered per intercalated ions i ie for Ax 1 AQ 1916 936 mAh Electrode surface area 0 001 or Characteristic mass 0 00 g Reference electrode unspecified m Offset potential vs Normal Hydrogen Electrode 0 000 Fig 81 Cell characteristics window for battery applications 8 Techniques and Applications Manual This window has been designed for battery electrode materials acting as intercalation electrode which is the case of several primary and secondary batteries It allows you to e Enter the physical characteristics corresponding to the active material of the working electrode This makes on line monitoring of the redox processes possible in term of normalized units molar amounts of intercalation e
24. E A AEE E EET 212 Techniques and Applications Manual Introduction EC Lab software has been designed and built to control all of our potentiostats single or multichannel SP 50 SP 150 SP 200 and SP 300 MPG MPG2 VMP VMP2 Z BiStat VMP3 VSP HCP 803 HCP 1005 CLB 500 EPP 400 and EPP 4000 Each channel board of our multichannel instruments is an independent potentiostat galvanostat that can be controlled by EC Lab software Each channel can be set run paused or stopped independently of each other using identical or different techniques Any settings of any channel can be modified during a run without interrupt the experiment The channels can be interconnected and run synchronously for example to perform multi pitting experiments using a common counter electrode in a single bath One computer or several for multichannel instruments connected to the instrument monitor the system The computer connects to the instrument through an Ethernet connection or with an USB connection With the Ethernet connection each one of the users is able to monitor his own channel from his computer More than multipotentiostats our instruments are modular versatile and flexible multi user instruments Once the techniques have been loaded and started from the PC the experiments are entirely controlled by the instrument s on board firmware Data are temporarily buffered in the instrument and regularly transferred to the PC which is used fo
25. EC Lab version 9 50 a multisinus measurement was introduced for the impedance measurement techniques 2 2 1 Principles of multisine measurements To spare time during impedance measurements especially in low frequencies range but also to avoid the measurement drifts if the system changes quickly with time it may be useful to use a multisine excitation signal Indeed to get information at different frequencies with an excitation signal the system has to be excited successively by one frequency at the time resulting in a very long experiment Indeed the total time taken for the complete analysis is the sum of the individual measurement times This is the case for the single sine measurement In multisine measurement all the frequencies are analyzed at the same time Then the use of Schroeder multisine simultaneous application of several sinewave allows the user to save a lot of time especially for measurement at low frequency 30 Techniques and Applications Manual The multisine signal is thus defined as the sum of sinusoids at different frequencies having the same programmable amplitudes A resulting in a time signal and different phases o with the following formula 1 N k 1 u t A gt cos 2IIf t _ with the phase 0 O 209 1 k 1 n 1 The EIS multisine measurement developed in EC Lab software is defined in order to minimize the crest factor defined by Cru With Ugy af 2 eff With multisi
26. EF i moo 0500 ooo pass 0 0000 pass Mo moo j Go back to sequence Ma fr POG ene Aa aaa for mg D timels PE AN Aa A E Fig 169 Special Modular Galvano Galvanodynamic detailed diagram The three modes of the Special Modular Galvano technique can be chained as sequences in the table in the order that the user wants Each of the parameters can be modified in its box But parameters like Range or Bandwidth must keep the same value for all the sequences Note that the first sequence has got the number N 0 To switch from a sequence to another one click on the desired row in the table For more details about the Table frame see the chronoamperome ry technique p 19 Note in this technique the first and the last data points of each current steps are not recorded automatically 3 5 4 SGCPL Special Galvanostatic Cycling with Potential Limitation This technique such as the GCPL technique corresponds to battery cycling under galvanostatic mode essentially i e with an imposed current but with possible potential limitations under current for both charge and discharge and test on potential values during open circuit period Additionally to the GCPL technique it is possible to limit the under current period by considering the value recorded with the analog input The main characteristics of this technique are the same than those of the GCPL one 190 Techniques and Applications Manual ik pass ooo T
27. Ewe to a maximum value if I gt 0 or to a minimum value if lt 0 and the charge from the beginning of the sequence AQ Ax for the whole step The maximum charge can be entered into mA h AQy or as a normalized charge related to intercalation electrodes Axy Once a limit is reached the experiment proceeds to the next step Rest even if the programmed time ty is not terminated These limits can be bypassed by entering 0 values into the controls Caution Applying a constant power during a discharge experiment corresponds to an increase of the current in absolute when the potential decreases The user must be careful to note the final current of the first constant power step For example let s consider a 30 watts power discharge applied to a battery with a 10 A booster We suppose that the potential limits of this experiment are 4 V and 2 5 V The initial current will be 7 5 A but the final current will be 12 A overload in current It will not be possible to go to the final current 3 2 4 Constant Voltage CstV The constant voltage CstV technique is specially dedicated to fuel cell s or photovoltaic cell s testing It is designed to apply successively several voltage steps to the cell s Between each voltage step an open circuit voltage period can be added 127 Techniques and Applications Manual RestfortR o hi mr iooojo Limit IdEwe dtl lt dER dt gg mh Record every dER 00 mv odtR 1 3 App Ejs 2
28. Fig 139 I Ewe and T vs time for the CPT experiment e First step set the initial temperature and turn to rest Set T sussun C sets the temperature Tj Rest Until lt dT dt gt lt dT C dtp h mn or forty h MN turns to rest until the temperature is stabilized or during to time The first limit reached stops the rest period A 0 value devalidates a limit If dT 0 or dto 0 then the rest duration will be to If only t is null the rest period will continue until the temperature is stabilized under dT dty limit And if both dTo dt and tp are null the rest is skipped but the temperature is also set to T value Record every dTpo C dEpo aan mV and dtpo mn S records on temperature dTpo potential dERo and time dtro resolutions The first condition reached defines a recording A zero value disables a recording condition e Second step potential scan Scan Ewe with dE dt mV s Defines the potential scan The software selects the smallest potential step according to the control potential resolution defined in the Advanced settings window see the EC Lab software manual for more details 156 Techniques and Applications Manual From Ei V vs Ref Eoc Ectrl Emeas to Ep V vs Ref Eoc Ei from a potential E defined in absolute vs Ref the reference electrode potential or versus a previous open circuit potential Eoc pr
29. ManmiG ieccined shes ctesaencd eed stasateece a a a i 67 GAOS eae nee en meinen mene ne moet oe ee ne eo ee ee eee eee 66 OOV gare ete oan Re mE RE Re a Ree en Ee ene NRE 65 Modular Galvano MG cncisiee io sci ee Soci a eS Oe eee asd 65 Modular Potentio GV scbecetneesssatsncysaeneasenenascancewenan casino E A ER E EAE 69 PotentodynaMNi Gizie po E esate cs sh etic est ce ah cats te ee 71 POLIO ANC actanel cities seitahelndiinelanaihahatndiiue naihohauaue maivahaudniielnaivohamadainei nai sahasuaenente 70 Modular P otenmtio MP scyce Ghat tte Groce tue Genter tit ica ah ee Gea aay ot Acai Gat 69 182 MOE CNO IE Victoaee keeles setae teehee Neato eh haat Son a ce ace Senha eRe eta ees Meenas aoe 48 Multielectrode Potentiodynamic Pitting MPP cccscccseeeceeeeceeeeseeseeeeseeeeeeeseeeeneeeeaes 161 Multielectrode Potentiostatic Pitting MPSP cccccccseccceeeceeseceeeeseeeceuseceeeeeeeseueeseeesees 165 MUNISING measurement serisinin tends uate aaed pated de nutea dda sntidynde sated aad den senadesntence atamie 30 Normal Pulse VOllammeney NPV ersen a deeded iv celanel deel Teele ease 57 Nyg is t Diagram aces eto an S a 38 Open CIRCUIT Voltage OO V a a ud sein aE E ENE 5 Pause technig e rasero e o e a iaa e a ED NiE SEa 78 PCGA GOMPACL DOCES S ia wssert eta esata oan waste N 89 PEIS BC S1 018 6 I ex CO meee eet eee eee Reet eee a OC EE RD ety SE ORE Cre ee 35 39 Olah ZAllON MCSISLANCC siea a niacin mdiancaiv
30. Modular Potentio As the Modular Potentio technique the SMP allows performing OCV potentiostatic and potentiodynamic periods It is possible to chain these periods in any orders and to perform loops that give a lot of flexibility Moreover an additional limit condition is added 182 Techniques and Applications Manual Go back to sequence N fr ERRI ant faces for Mig lo tirnels JE AVA wae A Fig 165 Special Modular Potentio OCV detailed diagram e Mode selection clicks on Mode OCV 0 Potentiostatic 1 or Potentiodynamic 2 to select the corresponding mode e Open Circuit Voltage Mode 0 The open circuit voltage is the same block as those reported for the SOCV technique section for more information e Loop goto N for ne time s each one of the OCV potentiostatic and potentiodynamic periods is represented by a single sequence If n is set to 0 the sequence lines are executed one after one Then an OCV potentiodynamic and OCV sequence for example will be programmed by 3 lines into the parameters table Setting Nn gt O will loop to a previous line Ns lt Ns for ne times Report to the battery techniques section 3 1 page 83 for more details on loops conditions lt is possible to loop to Ns 0 but Ns must be lt N current sequence line number 183 Techniques and Applications Manual PEE q 4 4 ae 0 1000 2AN m Go back to sequence Ng D TRA yT AAV YMRS for mg D
31. N 0 The number of loops starts while the loop block is reached For example on N 3 if one enters goto Ns 2 for Nn 1 time the sequence N 2 N 3 will be executed 2 times nN 0 disables the loop and the execution continue to the next line Ns Ns 1 If there is no next line the execution stops Corrosion Corrosion is the chemical or electrochemical reaction between a material usually a metal and its environment that produces a deterioration of the metal and its properties EVT E or versus Time This technique corresponds to the follow up of the corrosion potential when the circuit is open versus time During the measurement no potential or current is applied to the cell Fes fo tp f ho mn fpo000 3 Limit IdEywe dtl lt dE_ dt 90 m h Record ever dep 5 0 ri o dtp 0 0000 Fig 118 E orr VS Time diagram Rest for tr h mn S fixes a defined time duration tp for recording the rest potential or until dE dt lt dEp dt mV h stops the rest sequence when the slope of the open circuit potential with time dE dt becomes lower than the set value value 0 invalidates the condition Record Ewe every dEr mV resolution and at least every dtp S 131 Techniques and Applications Manual allows the user to record the working electrode potential whenever the change in the potential is gt dEr with a minimum recording period in time dtr Data recording with dEr resolution can red
32. Ref the reference electrode potential or versus Ese or Ei with pulses height Py mV pulses width Py ms step height S mV step time S1 ms The pulse train is made of pulses with pulse height Py amplitude and pulse width Pw duration Superimposed with a staircase of step height amplitude S and step time S duration Notice that only one point is recorded at the end of the potential pulse and one point before making two points during the S period The example above Fig 41 is given for a positive scan To perform a negative scan set E inferior to E and Sy to a negative value Scan rate mV s number of points these values are given as an indication and are calculated in the PC The scan rate is directly given by Sy 0 001S 7 and the number of points is roughly 2 E E Sy for the forward scan average over the last of each step points selects the end part of the potential step for the current average lt I gt calculus to exclude the first points where the current may be perturbed by the step establishment A value of 100 will take all the step points for the average and a value of 0 will take only the last point Note that the current average lt I gt is recorded at the end of the potential step to the data file enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential
33. Select the recording of the counter electrode potential e Select the recording of external signals pH T P using auxiliary inputs 1 2 and 3 3 1 1 3 PCGA Data processing 3 1 1 3 1 Compact function The Compact function is very useful in representing the incremental capacity of a battery The user has to represent dQ f Ewe in the graphic display see the application note 2 on our web site for more details Using the compact function a new variable can be created dQ which is the charge calculated every potential step 0 35 0 3 0 25 ha a cn yyw OP 0 1 0 05 0 05 3 4 3 6 3 0 4 42 Ewen Fig 82 Incremental capacity dQ vs Ewe graph red circles and X vs Ewe plot blue lines of a Li button cell 88 Techniques and Applications Manual 3 1 1 3 2 Intercalation coefficient determination Process Data Input Files 0 E C LabsD atas S amples PITT 2 Technique Potentiodynamic Cycling with Galanostatic Acceleration Processed File O EC Lab DataS amples PITT 2300604 1 IQenE mpp Load Add Remove Clear Variables To select from the input file To be added mode i Wl osred G Gol ma h error W s t control changes MW cycle number Wl Ns changes C O chargesma h counter ine Q dischange ma h times J Energy h controls Energy charge h Emen L Energy discharge h dq m h EJA E All P
34. at a particular potential preconcentration 68 Techniques and Applications Manual SS to Ne or He OLY period or Apply Es potential or Appl dEvdt potential scan moo a 1 2 a mm of Fig 59 Modular Potentio general diagram e Mode selection Click on Mode OCV 0 Potentiostatic 1 or Potentiodynamic 2 to select the corresponding mode 2 4 2 1 Open Circuit Voltage Mode 0 OC 0 Mode Potentiostatic 1 Potentiodynamic 2 Rest for tp oO ho m fogg Limit IdEwe dl lt dER dt gg mh Record every dEp oo mm or dtp o5000 Go back to sequence Net f RGIS Boks feces forme A timels re regi Hs 2 Fig 60 Modular Potentio OCV detailed diagram The open circuit voltage is the standard block so report to the OCV technique section for more information e Loop goto N for n time s each one of the OCV potentiostatic and potentiodynamic periods is represented by a single line in the grid parameters If n is set to 0 the sequence lines are executed one after another Then an OCV potentiodynamic and OCV sequence for example will be programmed by 3 lines in the parameters table Setting Nn gt 0 will loop to a previous line Ns lt N for ne times 69 Techniques and Applications Manual Report to the battery techniques section 3 1 page 83 for more details on loop conditions It is possible to loop to Ns 0 but Ns must be lt N current seque
35. be set to fixed value or relatively to the cell equilibrium potential Technique linker tool of EC Lab software used to link techniques in order to build a complete experiment with or without open circuit period between techniques Reverse Normal Pulse Voltammetry RNPV technique used in analytical electrochemistry to discriminate faradic from capacitive current This technique is made of increasing pulses with time that always come back to the beginning potential The current is sampled in the opposite way as for the NPV technique Run button that starts the experiment Scan rate speed of the potential sweep defined with the smallest possible step amplitude Square Wave Voltammetry SWV technique used in analytical electrochemistry to discriminate faradic from capacitive current This technique is made of successive positive and negative pulses according to the averaged potential sweep Stepwise Potential Fast Chronoamperometry SPFC Simple general electrochemistry technique used to loop quickly on two potential steps Triggers option that allows the instrument to set a trigger out TTL signal at experiment start stop or to wait for an external trigger in to start or stop the run Zero Resistance Ammeter ZRA technique used to perform measurements to examine the effects of coupling dissimilar metals or to perform some types of electrochemical noise measuremenis Zero Voltage Current ZVC technique similar to ZRA except th
36. before the pulse and near the end of the pulse The resulting current is the difference between these two currents It has a relatively flat baseline The current peak height is directly related to the concentration of the electroactive species in the electrochemical cell petEweto Ej 0 200 YO VE Eoc forty o hip mh f1O0000 E Scan E we from E to Ey 0 500 Wows Eoc th with pulses height PH 25 ri si T i E o pulses width Pay i ood ris Te l li laverage step height SH 5 0 rity a an a _ a step time ST 500 0 ms i 1 op average over the last 20 of each step Aree mognat aaa MERR a PRATER OF NENS ee Fig 40 DPV waveform ERange 24 24 Areca Ate Range 10 ma Bandwidth 7 Reverse scan to Ep 0 000 M oya Ref Fig 39 DPV detailed diagram Description e Initial potential Set Ewe to E vse V vs Ref Eoc Ectrl Emeas fort Pi sivusi mn S sets Ewe to the initial potential E This potential value can be set in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Eve controlled potential Eer or eeasured potential Emeas Notice that only the last point of this period is recorded at the time 0 e Pulse waveform Scan Ewe from E to E V vs Ref Eoc Ei 50 Techniques and Applications Manual defines the vertex potential as E either in absolute vs
37. bypass this test by entering p pass instead of a voltage value e Fourth step conditional test which proposes to go to the next sequence or to loop on a previous sequence Ns Ns lt Ns lf n is set to 0 then the technique executes the next sequence If the user wants to loop to a previous sequence line he has to fill the 2 last columns of the table Go to Ns and n cycles The end of the technique is obtained by setting Ns and n to O in the last sequence or setting Goto sequence Ns 9999 at any sequence which then will be the last one executed even if the next sequence has its settings Such a complete sequence corresponds to one line of the table This line is composed of the columns which represent the successive variables encountered when setting the diagram the current range and the loop conditions all parameters which must be set by the user see Warning 2 Note that it is always possible to force the end of a technique while it is running at any sequence sweep using the Modify button and setting Goto sequence Ns 9999 at the sequence one wants to stop 3 1 8 CLD Constant Load Discharge The Constant Load Discharge application has been designed to discharge a battery ata constant resistance The potentiostat is seen as a constant resistor by the battery R Ee ll limit Eys Fig 96 CLD control Il and measure Ewe sample vs time The constant resistance control is made by controlling the cu
38. control Record evey dq 1 000 m h 7 di foo pA or dt Limit the whole time to tg 6 hijo mh foo000 and AOI gt AQw 0 000 m h lt gt Aung 0 000 ERange 0wW 5 ena Fata Range i00m4 Bandwidth 7 l Restor tR f hijo mn foomo Limit IdEwe dtl lt dE_ dt 00 ri Record ever dip oo rity a dtp Hooo s fig Bex AGI gt Ay gaia EY 3 eos gt colo GL Goback to seq Net f JSG ante facta for ng 4 time js fatto say severe Fig 91 GCPL4 detailed diagram e first step galvanostatic period Set to Is pA A vs lt None gt Ictrl Imeas with Range and Bandwidth fixes the current value in absolute versus the previous controlled current previous sequence or versus the previous measured current The sign of the current value is for a discharge and for a charge when the positive electrode of the cell is connected to the working electrode cable red 99 Techniques and Applications Manual enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment lrange and Bandwidth defines the current range and bandwidth for this experiment Record every dE mV and dt sS defines the recording conditions during the galvano period These values can be
39. dQ mA h and at least every dt S in the constant potential mode the system acts as a coulometer and a recording is performed every time the charge increment decrement since the previous recording is gt dQ and or every dt time interval Limit AQ to AQn mA h lt gt AXy fixes the maximum charge change from the beginning of this sequence during the sequence This charge is equivalent to a Axy quantity which corresponds to a normalized charge related to intercalation electrodes enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment I Range and Bandwidth fixes the current range and bandwidth for this experiment e Second step open circuit period as in the GCPL technique turn to Rest for tp h mn S or until dEwe dt lt dEp dt mV h Record Ewe every dEr mV and at least every dtp S reports to the OCV technique description for more details section 2 1 1 page 5 e Third step test on the open circuit final potential as in the GCPL technique too test Ewe vs E V vs Ref Eoc Ei 86 Techniques and Applications Manual the test is performed according to the conditional value either gt if the open circuit sequence occurs after a charge I gt 0 or lt in the case of a discharge I lt 0 As seen previously
40. dt sS before the EIS measurement the user can apply an equilibration period with the ability to record the potential During this period no impedance measurement is done e Impedance scan Scan from fi kHz Hz mHz yHz to f kHz Hz mHz pHz defines the initial f and final f frequencies of the scan To have results more rapidly it is better to choice to scan from the highest frequencies to the lowest ones but it is possible to reverse the frequencies scan order with Ng points per decade in Logarithm spacing Ni nanan points from fi to ff in Linear spacing defines the frequencies distribution between the scan bounds f and f It is possible to select the number of points per decade Na or the total number of points N in linear or logarithm spacing Click on the Show frequencies gt gt button to display the list of scanned frequencies Note it is not possible to select Ng points per decade in linear spacing with amplitude V mV sets sinus amplitude to Va Equivalence with Vams is also given Note the following relationships between Va Vpp and Vams Va Vpp2 and Vams Vop 2 2 average N mesure s per frequency repeats Na measure s and average values for each frequency enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adj
41. example on N 3 if one enters goto Ns 2 for Nn 1 time the sequence N 2 N 3 will be executed 2 times Ne 0 disables the loop and the execution continue to the next line Ns Ns 1 If there is no next line the execution stops Report to the battery techniques section 3 1 page 83 for more details on loop conditions Thus it is possible to loop to the first instruction N 0 and the current instruction Ns Ns That is different from the battery experiments GCPL and PCGA where the first instruction has a special meaning and where there is still a loop on the current instruction Process A process function is associated with chronopotentiometry technique The variables that can be processed are the same as for the CV technique For more details about CP process see the previous CV part Note In this technique the first and last data points of each current steps are not recorded automatically 2 1 7 SV Staircase Voltammetry Staircase voltammetry SV is one of the most widely used techniques for acquiring qualitative information about electrochemical reactions SV like cyclic voltammetry provides information on redox processes heterogeneous electron transfer reactions and adsorption processes It offers a rapid location of redox potential of the electroactive species SV consists of linearly scanning the potential of a stationary working electrode using a triangular potential waveform with a potential step
42. la with lbp 2 la or the Root Mean Square RMS voltage related to la with Irus la V2 36 2 2 4 Visualisation of impedance data files 2 2 4 1 Standard visualisation modes Techniques and Applications Manual EC Lab software provides a full range of variables and visualisation modes defined by default When an impedance data file is displayed click on Selector to show all the variables and visualisation modes available with impedance data files Variables Representation Nyquist Impedance Representation Myguist Impedance wt Ewe vs t Bode Impedance ka Tl ra i d Nyquist Impedance Ewel O0 C Black Impedance I el va t IA O0 O C Bode Admittance j Seats O O Nyquist Admittance n Ei pe 4 d Black Admittance Phase Wdeg O O O Fig 25 Impedance graph plot imes O O selector ew O O O cycle number C L Range L Ref Ohmi C Im Ohm 0 L v Same s lection for all files Hide Additional ariables Frequencies Fig 24 Impedance data file selector Among the available variables the Impedance Z is calculated using Fast Fourier Transform function and the admittance Y is determined as Y 1 Z For both variables Bode Nyquist and Black diagrams can be plotted according to the EC Lab software s predefined graph visualization modes 37 Techniques and Applications Manual e Bode diagram for both impedance and admittance The Bode diagram is the plot of lo
43. must be plotted on X axis 40 Techniques and Applications Manual Hide Additional Yanables File Selection Files l CAEC Lab D atasS amples 19850_2POT_1 mpr parane Representation E vs t ka YI Y2 freq Hz fF O E Rel2 Ohm M E ImlZOhm A O E l Ohm F Phasel deg M E E limes s rr vf o A cycle number M E E RefOhm1 A O E Imr 0km O O VeOhm1 A A A Phase ideg N O E Same selection for all files keep previous aves process keep previous zoom Fig 31 File selection display select Z t plot in the scroll menu Then the following window is displayed to select frequencies to plot Frequencies 215 437 kHz 68 163 Hz 146 781 kHz 46 503 Hz 100 000 kHz 31 672 Hz 68 125 kHz 21 552 Hz 46 406 kHz 14 655 Hz 31 622 kHz 10 016 Hz 21 547 kHz 6 829 Hz 14 677 kHz 4 650 Hz 3 996 kHz 3 168 Hz 6 816 kHz 2 146 Hz 4 642 kHz 1 465 Hz 3 160 kHz 1 000 Hz 2 153 kHz 1 467 kHz 1 002 kHz 681 090 Hz 464 309 Hz 315 505 Hz 215 344 Hz 146 358 Hz 100 296 Hz M All frequencies Cancel Fig 32 Z vs time display used to select frequencies 41 Techniques and Applications Manual Choose the desired frequencies and click Ok The graphic representation will automatically display one trace for each chosen frequency In the graphic display Z f t is represented for the four different frequencies selected before 1 650 Ss E i a aE i E 146 358 Hz 1 600 een 315 5
44. not store every cycle A reverse button can be used to reverse the potential sweep when necessary without modifying the vertex potentials different from the Force button The technique is composed of e starting potential setting block 1 potential sweep with a vertex limit E4 2 potential sweep in the opposite direction with a vertex limit Es possibility to repeat n times the 1 and the 2 potential sweeps final conditional scan in the reverse direction to the previous one with its own limit Er Note that all the different sweeps have the same scan rate absolute value But it is possible to add sequences allowing to use different rates for each sequence The detailed diagram the following figure is made of three blocks 11 Techniques and Applications Manual m m m m m m m E 1 000 ph 1000 1 000 ee el 01000 So ho bo h E u 4 dE fot 100 py 47 0 ms Hold E dEN 1 0 mv Sane ost 4000 points per cycle Fig 6 Cyclic Voltammetry Advanced detailed diagram e Starting potential Set Ewe to Ej V vs Ref Eoc Ectrl Emeas sets the starting potential in absolute vs Ref the reference electrode potential in the cell or according to the previous open circuit potential Eoc or controlled potential Eet or Measured potential Emeas Hold E fort h MN S and record every dti S offers the possibility to hold the initial potential fo
45. on the current are available with the potentiodynamic mode either recording an averaged current lt l gt on each potential step or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ e Third step temperature scan Keep Ewe Ef during this step the potential is kept to Er Scan T with dT dt C mn with il Os soaa S fixes the scan rate dT dt in C mn or at the users convenience with the choice of the temperature increment in C and step duration in s Default choice of the system proposes a scan rate as close as possible as the requested one and obtained with the smallest possible step amplitude The temperature and the time step values are multiples of 0 01 C and 20 ms respectively Due to the TCU the minimum time value is 1 s from T to T C fixes the final temperature scan value T Or until I gt Ip WA for tp s or I gt lIn mA fixes the threshold pitting current lp during tp or Im to detect Record e lt I gt over the last of the step duration averaged N voltage steps el every dl HA or dt S two different recording conditions on the current are available with the potentiodynamic mode either recording an averaged current lt l gt on each potential step or recording an instantaneous current with a time variation and or an instantaneous curr
46. pC KC defines the potential and sequence charge limits The E limit is depending on the charge sign the limit is Ewe gt E if I gt 0 188 Techniques and Applications Manual Ewe lt E else To cancel the limits type p for pass into the E edition box and zero for AQy For the galvanostatic mode AQ is not accessible and is calculated from and ts AQm I ts And Analog In 1 Analog In2 lt gt L Vfortz S sets limits of the sequence considering the value recorded with the analog input If the value reached L during t then the sequence is stopped and the next sequence is applied e Galvanodynamic Mode 2 Scan with di dt mA s with pA A s defines the scan rate By the same way than for the Modular Potentio technique entering the dl dt value will automatically calculate the dl and dt values in order to minimize the current steps dl Nevertheless one can enter dl and dt directly from li pA A vs lt None gt Ictrl Imeas to pA A vs lt None gt Ii defines the initial l and final l current of the scan Recording and limits are the same than for the galvanostatic period except that dQ and AQy that can be accessible for the galvanodynamic mode With I Range and Bandwidth fixes the current range and the bandwidth for this experiment 189 Techniques and Applications Manual olele 001 000 l CEE ESIESIES
47. range and the bandwidth damping factor of the potentiostat regulation e Reverse scan Reverse scan towards vertex potential E V vs Ref Eoc Ei Techniques and Applications Manual runs the reverse sweep towards a 2 limit potential The vertex potential value can be set in absolute Ref or according to the previous open circuit potential Eoc or according to the potential of the previous experiment E e Repeat option for cycling Repeat n times repeats the whole sequence n time s Note that the number of repeat does not count the first sequence if Ne 0 then the sequence will be done 1 time ne 1 the sequence will be done 2 times Nn 2 the sequence will be 3 times e Final potential Reverse scan yes or no towards Ep V vs Ref Eoc Ei gives the possibility to end the potential sweep or to run a final sweep with a limit Er Option Force E E While the experiment is running clicking on this button allows the user to stop the potential scan to set the instantaneous running potential Ewe to E or E 2 according to the scan direction and to start the reverse scan Thus E or and E 2 are modified and adjusted in order to reduce the potential range Clicking on this button is equivalent to click on the Modify button enter the running potential as E or E and validate the changed parameters with the accept button This button allows the user to perform the operation in a faster
48. resolution adjustment Range Bandwidth sets the current range and bandwidth values for the whole experiment Note It is highly recommended to not use the automatic current range with pulsed techniques The resolution of each range is different and dynamic current range changes may lead to spikes on the plot e Reverse scan definition O Reverse scan towards E V vs Ref Eoc Ei checks Reverse scan to perform a scan towards E either in absolute lt None gt or versus Esec or Ei Running the settings defined into Fig 39 will result in the following output 51 Techniques and Applications Manual 0 26 0 25 jas 0 24 123 egal f A pe 0122 HAH 127 no 0 20 ae i ag p HAL AA m _ lin 2S DAE 017 N i ie A liens 0 15 4 D14 4 fee ME 0134p 0 12 a 0 11 4 O10 4 Ewes 0 0 0 5 1 0 Ia 20 2 5 3 0 time s Fig 41 DPV output Ewe vs time These variables are stored in the DPV raw files mpr state byte time s control V lt l gt mA Q Q mA h And the next variables are calculated from lt l gt to save size on disk forward mA lt l gt values at the end of the pulses lp on Fig 41 reverse mA lt I gt values before the pulses lbp delta A difference between lt l gt values before and at the end of the pulse lp lbp 52 Techniques and Applications Manual delta pA O02 0
49. right corner of the block the approximate experiment duration is indicated as information for the user During the Run several parameters remain accessible for modification such as the min and max frequencies and the number of points per decade 34 Techniques and Applications Manual e Repeat Repeat for n time s allows for repeating PEIS measurements in order to represent Z evolution vs time see below E Range enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range Bandwidth Sets the current range and bandwidth values for the whole experiment e Sequence repetition The last part of this technique is dedicated to repeat sequences when many sequences are done Indeed since the version 9 9 of EC Lab software it is possible to add sequence in impedance measurements This tool is convenient to spare time indeed during the same experiment it is possible to work in single sine mode at high frequencies and in mutisine mode at low frequencies or to change the sinus amplitude When the box Increment cycle number is ticked each sequence will be considered as a cycle This tool is useful to fit EIS data files with ZFit 2 2 2 2 Additional features e lt is possible to add sequences This could be very useful to do a first part of the high frequenc
50. sinus amplitude to Va Wait for py period before each frequency measurement offers the possibility to add a delay before the measurement at each frequency This delay is defined as a part of the period Of course for low frequencies the delay may be long average N measure s per frequency repeats Na measure s and average values o Compensate at defines the level of the measured uncompensated resistance R that will be compensated to define IR The user can check the box to consider the compensated resistance in the following technique or not enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment Range Bandwidth sets the current range and bandwidth values for the whole experiment 2 6 3 Cl Current Interrupt Some set up induces ohmic drop iRu In that case ohmic drop can be significant and then affects the measurement A method to determine estimate the resulting uncompensated resistance Ru is to perform the Current Interrupt Cl method A current step is applied and the Ru value is determined by the ratio between the measured voltage and the measured current The Cl technique enables the user to determine the resistance when the current step is applied E2 E1 12 11 and or interrupted E4 E3 14 I3 Then an averaged correc
51. software Abbreviations Description tr Rest time dEpr dt Limit condition on a variation of the WE potential dER Recording condition on a variation of the WE potential dtr Recording condition on a variation of time E Initial potential Ref Reference electrode potential versus which WE potential will be applied mere Open circuit potential versus which WE potential will be applied Eeri Last controlled potential versus which WE potential will be applied Eo Last measured potential versus which WE potential will be applied ti Time duration to Hold Ei dti Recording condition on a variation of time dE dt Potential scan rate E First vertex potential t Time duration to Hold E dt Recording condition on a variation of time N Number of averaged voltage steps between two data points Range Current range E gt second vertex potential to Time duration to Hold E2 dts Recording condition on a variation of time Ne Number of repeated cycles f cycle recording frequency E Final potential t Time duration to Hold E dt Recording condition on a variation of time ee Minimum current Limit as Maximum current Limit AQu Maximum total Charge variation dl Recording condition on a variation of current dQ Recording condition on a variation of charge Ng Previous sequence to go back to ls Current step applied ts Time duration to Hold lotr Last controlled current versus which the cell current will be applied ae Last measured curren
52. steps every dl pA nA pA mA A or dt S Two different recording conditions on the current are available with the potentiodynamic mode either recording an averaged current lt l gt on each potential step or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment Range and Bandwidth Define the current range and the bandwidth for the whole experiment Range is automatically set according to and values 3 2 1 2 Process Associated with the I V characterization an analysis is available for this section offering the determaintaion of the following parameters Short Circuit Current which corresponds to the maximum current when E 0 V the Open Circuit Voltage E which is the potential when the current is equal to zero ampere the theoretical power Pr which is defined by the following relationship Pr he X Eoc the maximum power _ the fill factor FF which is the ratio of Puax and Pr the efficiency can also be calculated 3 2 2 Constant load discharge The Constant Load Discharge application has been designed to discharge a device at a constant resistance The potentiostat is seen as a constant
53. suppose that the potential limits of this experiment are 4 V and 2 5 V The initial current will be 7 5 A but the final current will be 12 A overload in current It will not be possible to go to the final current 3 1 9 2 Application of the CPW technique The constant power technique is commonly used for a Ragone plot representation power vs energy The usual technique consists of successive sequences made with discharge to P 2 watts with n the number of the sequence no 0 Open circuit period after the discharge The discharge step is stopped when a minimum potential value is reached One can see the change of current and potential during a CPW experiment versus energy on the figure below For a constant power discharge the current decreases in the negative direction but it increases in absolute to compensate the fall of potential 111 Techniques and Applications Manual Ewen 5 2 0 fe a i Energi h Fig 100 E measured blue line and adjusted red circles evolution vs energy during a CPW experiment on a Li ion battery 1 35 A h P 8 W The plotted current values are absolute values negative in reality In order to have a constant power the working electrode potential decreases when the current increases in absolute The power vs energy plot for a Li ion 1 85 A h battery is presented on the figure below Each constant power is separated with an OCV period limited with a potential variation dEp dt
54. the 0 V potential is established Record lt I gt and Q every dQ mA h and at least every dt S defines the recording conditions on the charge and time Each one of these parameters can be entered simultaneously but the first condition reached decides the recording A zero value cancels the recording condition Limit AQ to AQy mA h limits the charge per n loop to AQmu Setting AQy to O cancels the test enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment Range Bandwidth sets range and bandwidth for the whole experiment e OCV The open circuit voltage is the standard block so report to the OCV technique chapter for more information e Repeat Repeat n time s repeats the ZRA and the OCV blocks n times If n is set to O then these blocks will be done only once N 1 will execute the blocks twice Limit Q to Qy mA h limits the total charge from the beginning of the experiment to Qr Setting Q7 to 0 cancel the test 3 3 13 ZVC Zero Voltage Current The ZVC technique is the same as the ZRA technique except that the control apply O V is done between the working electrode WE and the reference electrode REF rather than between the working electrode WE and the counter electrode CE Therefo
55. the Ese potential has the opposite sign of Ewe Limit AQ to AQy mA h lt gt AxXy Fixes the maximum charge change from the beginning of this sequence This charge is equivalent to a Axy quantity which corresponds to a normalized charge related to intercalation electrodes e Open Circuit Voltage The open circuit voltage is the standard block so report to the OCV or GCPL techniques sections for more information e Potential test Test Ewe Ece VS E_ V The third step is the test on the open circuit final potential This test is skipped if there is no OCV period tr 0 The test performed takes the conditional value gt or lt depending on in the open circuit sequence occurs after a charge gt 0 or a discharge I lt 0 And the above 2 steps will be repeated until the working electrode potential reaches the limiting condition Eye E after a charge or Eye lt E after a discharge Note the user can bypass this test by entering p pass instead of a voltage value e Loop Next sequence or goto sequence N Ne Sse time s loops to a previous sequence Ns lt N Ne time s Set Nn O to cancel the loop and go to the next sequence N 1 Note Ege and Ewe Ece recording are forced into the GCPL2 data files 3 1 4 GCPL3 Galvanostatic Cycling with Potential Limitation 3 The GCPL3 application is the same as the GCPL2 technique with the ability to hold the potential af
56. the current is reached on the channel The EC Lab software uses a particular Process Data function Multi Pitting Statistics which gives the mean values and the mean quadratic deviations of the final rest potentials and pitting potentials obtained from all the channels used in the experiment 162 Techniques and Applications Manual 3 3 10 1 Description alle c hoo az no a cle lt e ope Z q E 4 i 4 4 ii dE vot 100 p 7 600 0 ms Fig 144 Detailed diagram of the Potentiodynamic Pitting technique e First step a rest potential or open circuit sequence Rest for tp h uo MN a S fixes a defined time duration tpr for recording the rest potential or until dEwe dt lt dEp dt mV h gives the user the ability to shorten the open circuit period at the time when the decay of the potential is lower than a given value Record Ewe with dEp mV resolution and at least every dtg S allows the user to record the working electrode potential whenever the change in the potential is gt dEr or every dtp time interval Data recording with dER resolution reduces the number of experimental points without loosing any interesting changes in potential When there is no potential change only points according to the dtg value are recorded but if there is a sharp peak in potential the rate of the potential recording is governed by the potential recording resolution e Seco
57. time s ZETAN AST nee f on Fig 166 Special Modular Potentio potentiostatic detailed diagram e Potentiostatic Mode 1 Set Ewe to Es V vs Ref Eoc Ectrl Emeas sets the potential to a FIXED value vs Ref the reference electrode potential or RELATIVELY to the previous open circuit potential Esc or to the previous controlled Eet or measured Emeas potential in linked experiments or linked sequences for t ieee mn S enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range and Bandwidth fixes the current range and the bandwidth for this experiment Record I every dl pA A dQ fA h A h pC kC and dt lt I gt every dts sS 184 Techniques and Applications Manual You can record either an instantaneous current value or an averaged current value lt I gt The recording conditions during the potential step depend on the chosen current variable For the instantaneous current the recording values can be entered simultaneously then the first condition is reached and determines the recording A zero values disable the recording for each criterion For the averaged current the user defines the time for the average calculation In that case the data points are recorded in the channel board memo
58. to spikes on the plot SWV recorded and calculated variables The variables below are stored into the SWV raw files mpr state byte time s control V g Ewe V lt l gt mA Q Q mA h And the next variables are calculated from lt I gt or the potential to save size on disk forward mA lt I gt values at the end of the pulses lp reverse mA lt l gt values before the pulses lbp delta pA difference between lt l gt values before and at the end of the pulse lp lbp E step V step potential value resulting from the potential sweep and used to plot the current 2 3 3 DNPV Differential Normal Pulse Voltammetry Originally introduced as a polarographic technique performed at a DME the Differential Normal Pulse Voltammetry is a sensitive electroanalytical technique very similar to the DPV technique with a pulsed potential sweep The potential pulse is swept from an initial potential E to a final potential Ey There are two main differences with the DPV technique first the pulse waveform is made with a prepulse Sy amplitude with PPw duration before the pulse Py amplitude with Pw duration and second the potential always comes back to the initial potential E after the pulsed sequence E is assumed to be the potential where no faradic reaction occurs The plotted current is the difference of both currents measured at the end of the pulse I forward and the end of the prepulse I reverse
59. value and duration Record Ewe every dE mV and at least every dts s limits the recordings conditions in voltage variation and or time variation I Range and Bandwidth fixes the current range and bandwidth for this experiment e Conditional test which proposes to go to the next sequence or to loop on a previous sequence Ns Ng lt Ns ET Techniques and Applications Manual 3 1 13 RPI Resistance Profile Importation This technique consists to apply various resistance values on a battery during a defined duration This technique is specially designed to fit with the urban driving patterns designed to test EV batteries The particularity of this technique is the large number of Sequences available and the fact that the experimental settings can be defined by importation of a text file Note that experimental limits are not present in the setting it is highly recommended to use safety limits located in the Advanced Setting window to avoid overcharge or overdischarge of the batteries The text file importation columns are time s differential or absolute and resistance Ohm Start discharge on A 10 kOhm forts D h Ho mn fo ooo F Record Ewe ever dE i mi and at least every dtg 1 ooo0 amp Range 10 mA A medium eee eee Bandwidth E medum Gobackto seq Ns 0 RGIS VATS facta for nge E timels E A sey waaay Fig 110 RPI detailed diagra
60. vs Ret forty 0 hho mn oooog Lirnits Il max pass ma l min pass ma AO AOM O00 m amp h peoa I evem dl Q000 WA d f 8 E Range gwW 5W eno Aad Range Auto Bandwidth Ae medium Goback to sequence Ne p SIGS ante facta for Mig E tmel Aaa ease ag A Fig 116 Constant Voltage detailed diagram e Rest period The rest period is an open circuit voltage period Refer to the OCV description for more details e Potential step with data recording conditions 1 Potential step Apply E V vs Ref Eoc Ectrl Emeas the potential step is defined in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Eoc controlled potential Eet or measured potential Emeas for tj i E MN nanana S fixes the potential step duration 128 Techniques and Applications Manual limit I to Imax PA A and AQ lt AQy ___ fA h A h pC kC linin eens pA A curtails the step duration if the current or charge limit is reached If the limit is reached the loop condition go to Ns for n times if set is not used and the program continues to the next sequence N 1 The AQ value is the integral charge for the current sequence This value is not reset if there is a loop on the same sequence Ns N O values disable the tests 2 Recording conditions Record I ev
61. way when the limit potentials have not been properly estimated and to continue the scan without damage for the cell Note it is highly recommended to adjust the potential resolution according to the experiment potential limit This will considerably reduce the noise level and increase the plot quality Graph tool Process data to Generate cycles Since version 9 20 of EC Lab software it is no necessary to process the data file to generate the cycle number anymore Now the software is autonomous to generate the cycle number by itself For data files recorded before with older versions the user must process the file to generate the cycle number Note the automatic cycle number generation is available only with the CV and the CVA techniques Let s consider a data file made with an old software version If the CV experiment is made of several cycles the user can highlight the desired cycles The way to do that is 1 In the main menu bar click on Analysis General Electrochemistry Process data The following window appears Techniques and Applications Manual Process Data zl i Input File C AEC Lab4Data s amples CY platinum 10 cycles mpr Processed File C EC Lab Data Samples C platinum 10 cycles_d mpp Varables To select from the input file To be added mode cycle number osred E G Gol ma h Error 1 0 chargerm h control changes 1 d
62. 0 mes step height SH 100 m average over the last 100 4 of each step AAS aac cee a FREE AY a ce A aaa T be ERange 24 24 een Fae Range 10 m Bandwidth 7 Fig 44 SWV waveform Reverse scan to Ep 0 000 Y VE Ref r Fig 43 SWV detailed diagram Description e Initial potential Set Ewe to Ej V vs Ref Eoc Ectril Emeas fort i EERE mn S sets Ewe to the initial potential E This potential value can be set in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Esc or controlled potential Eer or measured potential Emeas Notice that only the last point of this period is recorded at the time 0 e Pulse waveform Scan Ewe from E to E V vs Ref Eoc Ei defines the vertex potential as E either in absolute vs Ref or versus Eg or Ei with pulses height Py mV pulses width Py ms step height S mV The pulse train is made of pulses with pulse height Py amplitude and pulse width Pw duration around the averaged potential scan The scan increment is defined by staircases of step height amplitude Sy and step time S duration Notice that only one point is recorded at the end of the potential forward pulse and one point at the end of the potential reverse pulse making two points during the S period The settings above Fig 43 are given for a positive scan To perform a negative scan set
63. 0 pA E Ranges 25 25 Y el PTER Fae Range Auto Bandwidth 7 m pernod 10 000 s scan rate 0 200 Vis Fig 17 Staircase Voltammetry detailed diagram e Starting potential Set Ewe to Ej V vs Ref Eoc Ectrl Emeas sets the starting potential in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Eoc or controlled potential Eg or Measured potential Emeas e Frequency and Potential range definition with measurement and data recording conditions Apply a sinusoidal potential scan With frequency fs kHz Hz mHz uHz Allows the user to set the value of frequency which will define the scan rate Between vertex potential E1 V vs Ref Eoc Ei Fixes the first vertex potential value in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Esc or previous potential E And vertex E2 V vs vs Ref Eoc Ei Fixes the second vertex potential value in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Eoc or previous potential E Repeat n times repeats the whole sequence n time s Note that the number of repeat does not count the first sequence if ne 0 then the sequence will be done 1 time ne 1 the sequence will be done 2 times Nn 2 the sequence will be 3 times Record every dt s and dl
64. 05 Hz lt _ae ____2 __ _ _4 __ ge _ _ _48e ___48e od t Z Ohm 1 500 eee eee 681 090 Hz 1 450 6 816 KHz _ 9 a ee i _ _ _ oe e 1 400 time s Fig 33 Graphic display for four different frequencies 2 2 5 Staircase Electrochemical Impedance Spectroscopy The SPEIS and SGEIS powerful techniques are designed to perform successive impedance measurements on a whole frequency range during a potential sweep SPEIS or during a current sweep SGEIS The main application of these techniques is to study electrochemical reaction kinetics along voltamperometric I E curves in analytical electrochemistry Thus these techniques find all their interest in studying the complexity of non stationary interfaces with faradic processes where the total AC response whole frequency range is required Another common application of such techniques is semi conductor materials study For these stationary systems only two or three frequencies for each potential step are required to determine the donor density and the flat band potential 2 2 5 1 SGEIS Staircase Galvano Electrochemical Impedance Spectroscopy With the SGEIS technique the potentiostat works as a galvanostat and applies a current sweep staircase shape An impedance measurement whole frequency range can be performed on each current step The user can also select several frequencies The SGEIS experiment performs imped
65. 15 mpr C Documents and Settings sebastens manips VMPIl seb corrosionshMPPSMPP4 1_6 mpr C Documents and Settings sebasten manips VMEPI seb corosion MPP ihMPP4 1_5 mpr Load Add Remove Statistics channel E init W 1 398 1 061 1 48 1 445 E oc i 1 370 1 045 1 399 1 433 Ep 629 ae Lam 0 555 lt E inito 1 065 TE irit ZE ocv gt 1055 CE oc lt E p gt 0 435 Ep W Print Settings Copy Print Close Fig 146 Multi pitting statistics window Report to the multipitting statistics process for more details in the EC Lab software manual 3 3 11 MPSP Multielectrode Potentiostatic Pitting Pitting corrosion occurs when discrete areas of a material undergo rapid attack while the vast majority of the surface remains virtually unatfected The MPSP technique corresponds to studying pitting occurrence under applied constant potential This technique is especially designed to study pitting on several electrodes in the same electrochemical cell First there is an open circuit sequence where the working electrode potential is recorded for a given time or until its time variation is lower than a defined limit Then the system applies a constant potential which can be the potential value reached at the end of the open circuit period plus a given potential offset or a defined value until the current reaches a value defined as the pitting current At the end of the technique the working electrode is disconnected 165 Tec
66. CIC VONAMIMENY zaria o E cd hae kG ae ae 5 2 1 3 CVA Cyclic Voltammetry Advanced cccccccseecceeeceeeeseeeseeeeceeseeeesaueeseeesaeeeseees 11 2 1 4 Linear Sweep VoltammMetry LSV cccccceccceeccceeeceeeeceeeeseeeseeeesseesseeeseueeseeeseeeesees 15 2 1 5 Chrono I Q Chronoamperometry Chronocoulometry ccceceeeeeeeeeeeeeeeeeeeeens 16 ZA20 CPS CHIOMODOTEMUOIMEIY x sied ce nnleohetn tess cos Sheba cana a a 20 AL OV OlalrGASe V OWAINIMGIY serre S 23 2 1 8 LASV Large Amplitude Sinusoidal Voltammetry ccccecceeseeeeceeeeeeeeeeseeeesseeeess 26 2 1 9 Alternating Current Voltammetry ACV cc ccccccseceesseeeseeeeseeeeseeeesseeeeseeeesaaeeees 28 2 2 Electrochemical Impedance Spectroscopy ccccseeccssecceeeeeeeeseeeeseeeeaeeeeeeeeseeeeaes 30 2 2 1 Principles of multisine measurements ccccsccceeecseeceeeceeeceeeceeeceeecseeceeesseeneeenes 30 2 2 2 PEIS Potentiostatic Impedance cccccccceecccseecececeeeceeeeceueecseeceueessueeseeessueensss 32 Beer IDCSCHIDUOM arama pantite annus abide aane Mens haan deho ban bens bannns MeO ide T RD aa 32 222 2 Additional features enerne er ea EE ended dal PETTE LER PERICE KERESNI TES 35 2 2 39 GEIS Galvanostatic Impedance sniseineiensiinen aa 35 2 2 4 Visualisation of impedance data files cccccccccccsececeeeeeeeeeeeeeseeeeeeeeseueeaeeeseeeenees 37 2241 Standard ViSualiSatlon MOSS oxieicwechecs seeds ails wecbecsgeed
67. E inferior to E and Sy to a negative value Scan rate mV s number of points These values are given as an indication and are calculated in the PC The scan rate is directly given by S 0 001S7 and the number of points is roughly 2 E E Sy for the forward scan average over the last Of each step points 54 Techniques and Applications Manual Selects the end part of the potential step for the current average lt I gt calculation to exclude the first points where the current may be disturbed by the step establishment A value of 100 will take all the step points for the average and a value of 0 will take only the last point Note that the current average lt I gt is recorded at the end of the potential step into the data file enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment IRange Bandwidth sets the current range and bandwidth values for the whole experiment e Reverse scan definition O Reverse scan towards E V vs Ref Eoc Ei Checks the Reverse scan box to perform a scan towards E either in absolute vs Ref or versus E or Ei Note It is highly recommended to not use the automatic current range with pulsed techniques The resolution of each range is different and dynamic current range changes may lead
68. EC Lab Software Techniques and Applications Version 10 1x February 2011 BioLogic Science Instruments V Equipment installation WARNING The instrument is safety ground to the Earth through the protective conductor of the AC power cable Use only the power cord supplied with the instrument and designed for the good current rating 10 Amax and be sure to connect it to a power source provided with protective earth contact Any interruption of the protective earth grounding conductor outside the instrument could result in personal injury Please consult the installation manual for details on the installation of the instrument General description The equipment described in this manual has been designed in accordance with EN61010 and EN61326 and has been supplied in a safe condition The equipment is intended for electrical measurements only It should be used for no other purpose Intended use of the equipment This equipment is an electrical laboratory equipment intended for professional and intended to be used in laboratories commercial and light industrial environments Instrumentation and accessories shall not be connected to humans Instructions for use To avoid injury to an operator the safety precautions given below and throughout the manual must be strictly adhered to whenever the equipment is operated Only advanced user can use the instrument Bio Logic SAS accepts no responsibility for acciden
69. Ectrl Emeas to E V vs Ref Eoc Ei from a potential E defined in absolute vs Ref the reference electrode potential or versus a previous open circuit potential Eoc previous controlled potential Een or previous measured potential Emeas to E vertex potential defined in absolute or versus E or Ei Until I gt lp pA A after t S fixes the threshold pitting current lp to detect Setting of a blanking time t permits to eliminate a possible large peak of current when just applying the initial potential step in case of large AE value enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment Range and Bandwidth defines the current range and bandwidth for the entire experiment Range is automatically set according to and l values Record lt I gt over the last of the step duration averaged N voltage steps every dl pA nA A mA A or dt S Two different recording conditions on the current are available with the potentiodynamic mode either recording an averaged current lt l gt on each potential step or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ Third step Hold potential Hold E Until I gt lp if the curre
70. Hz defines the initial f and final f frequencies of the scan To have results more rapidly it is better to scan from the highest frequencies to the slowest ones but it is possible to reverse the frequencies scan order with Ng points per decade in Logarithm spacing Ni nonan points from fi to ff in Linear spacing defines the frequencies distribution between the scan bounds f and f It is possible to select the number of points per decade Ng or the total number of points N in linear or logarithm spacing For example a scan from fi 100 kHz to f 1 kHz with Ng 5 points per decade in logarithm spacing will perform measures at the following frequencies in kHz 100 63 1 39 8 25 1 15 8 10 6 31 3 98 2 51 1 58 1 and a scan from fi 100 kHz to f 1kHz with N 11 total number of points in linear spacing will make measures at the following frequencies Hz 100 90 80 70 60 50 40 30 20 10 1 Click on the Show frequencies gt gt button to display the list of scanned frequencies Note it is not possible to select Ng points per decade in linear spacing with a sinus amplitude I mA sets the sinus amplitude to la average N mesure s per frequency repeats Na measure s and average values for each frequency enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential r
71. Lab software manual for more details From Ej V vs Ref Eoc Ectrl Emeas to E V vs Ref Eoc Ei from a potential E defined in absolute vs Ref the reference electrode potential or versus a previous open circuit potential Esc previous controlled potential Een or previous measured potential Emeas to E vertex potential defined in absolute or versus E or Ei Record lt I gt over the last of the step duration averaged N voltage steps every dl pA nA PA mA A or dt S two different recording conditions on the current are available with the potentiodynamic mode either recording an averaged current lt l gt on each potential step or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range and Bandwidth defines the current range and bandwidth for the whole experiment Range is automatically set according to and l values Third step reverse scan O Reverse scan with same scan rate towards final limit E2 V vs Ref Eoc Ei defines the reverse scan up to the final potential E gt This potential can be defined in absolute or versus previous E or Ei e Fourth ste
72. The Modular Galvano technique enables the user to perform combinations of OCV galvanostatic and galvanodynamic periods It is possible to chain these periods in any order and to perform loops It gives a lot of flexibility in creating galvano techniques The galvanodymamic mode can be used to study stepwise electron transfer reactions and multicomponent systems 64 Techniques and Applications Manual to Ne or Wes OC period or Apply Is or Apply didt moiaimf oOo mm of End Fig 54 Modular Galvano general diagram e Mode selection Click on Mode OCV 0 Potentiostatic 1 or Potentiodynamic 2 to select the corresponding mode Then the detailed diagram appears To select the second sequence N 1 click on the corresponding row in the Modular galvano table see below 2 4 1 1 Open Circuit Voltage Mode 0 a OLY D0 Hode Galvanostatic 1 Galvanodynamic 2 Rest fortp oO hi mf oooo le Limit IdEwe dtl lt dEp dt 99 miveh Record every dEp oo mm or dtp o5000 Go back to sequence NM E ERR ake jaca for Mig E imels AAY AMS SARACA Fig 55 MG OCV detailed diagram The open circuit voltage is the standard block So report to the OCV technique section 2 1 1 page 5 for more details e Loop Go back to Ns fornc time s each one of the OCV potentiostatic and potentiodynamic periods is represented by a single line in the grid parameters If n is set to 0 the sequence l
73. X and cycle number are also available as with other GCPL applications For more detail see the GCPL application 3 1 6 3 Application One classical application of this technique can be to follow the ohmic drop Ri evolution with aging of a Li ion cell after several charge discharge cycles Another application can be to determine the internal resistance of the battery versus time 103 Techniques and Applications Manual Ewe V UU Gia Haa 5 3508 5 3508 5 3508 5 3508 5 3808 5 3808 time Fig 94 GCPL 5 processed file display for Ri determination 3 1 7 GCPL6 Galvanostatic Cycling with Potential Limitation 6 This technique corresponds to battery cycling under galvanostatic mode essentially i e with an imposed current but with possible potential limitations under current for both charge and discharge and tests on potential values during open circuit period At the user s convenience the potential limitations can lead to different options e Skipping to an open circuit potential period or to the next imposed current sequence e Switching from imposed current mode to imposed potential mode by maintaining for a given time the potential of the working electrode at the limit potential once it is reached At the opposite of the GCPL1 technique the floating mode potential control and hold at a given value is not done between Refi and Ref2 cables but between Ref1 and Ref3 cable This technique offers the user the possibility to fo
74. a direct linear conversion in the range defined by the user between the min and the max value 179 Techniques and Applications Manual External Devices RDE Configuration Channel Device Type Device Name Analog QUT Analog IN 1 Convert Convert EM with 100 E E 5 YW mas with 10 W D E D W min D Vv Manual Control Analog IN 2 TC fon Convert E V to DeltalFi Chm v with 10 Wica 1000 Ohm mas 10 Woa 1000 Ohm min 0 Fig 162 External devices configuration window The user must define several parameters to configure the external to record measure data via analog input 1 and 2 right column The way to proceed for the configuration is described below 1 Choose the channel to configure Each channel can be configured for a specific device One channel can record one device and the other one another device 2 Select the Device Type in this case other 3 The user must tick the box to activate the selected Analog input 4 In the activated frame the user must define the conversion between the input voltage and the variable to plot This is a direct linear conversion in the range defined by the user between the min and the max value 5 The user can also define the name and the unit of the variable he wants to display Click on Custom Variables The figure below is displayed 180 3 5 1 Techniques and Applications Manual Custom Units absorbance U 4 resistance Oh
75. ability to shorten the open circuit period at the time when the decay of the potential is lower than a given value Record Ewe with dEp mV resolution and at least every dtp S allows the user to record the working electrode potential whenever the change in the potential is gt dEr or every dtr time interval Data recording with dEr resolution reduces the number of experimental points without losing any interesting changes in potential When there is no potential change only points according to the dtp value are recorded but if there is a sharp peak in potential the rate of the potential recording is governed by the potential recording resolution e Second step potential scan Scan Ewe with dE dt mV s defines the potential scan The software selects the smallest potential step according to the control potential resolution defined in the Advanced settings window see the corresponding section in the EC Lab software manual for more details From Ei V vs Ref Eoc Ectrl Emeas to E V vs Ref Eoc Ei 123 Techniques and Applications Manual from a potential E defined in absolute vs Ref the reference electrode potential or versus a previous open circuit potential Eoc previous controlled potential Een or previous measured potential Emeas to Ep value defined in absolute or versus Eg or Ei Record lt I gt over the last of the step duration averaged N voltage
76. actice is to select E in a region where the electroactive species of interest does not react at the electrode The current is sampled at a time t near the end of the pulse and at a time t before the pulse The plotted 57 Techniques and Applications Manual current is the difference of both currents measured at the end of the pulse forward and at the end of the period previous to the pulse reverse SetEweto Ej 0500 Mi yS Rel forty o hA ma Oooog Scan Epe from Ej to Ey 0500 vs Ref with pulses height PH AOO m pulses width Pyy 250 ms step time ST 1000 ms average over the last foo of each step Ae popisi nee aati MATRA anes PADENA ovo U E Fig 48 NPV waveform ERange 2w 2W e STENAR Aa ad Range 10 m Bandwidth 7 m Fig 47 NPV detailed diagram Description e Initial potential Set Ewe to Ej V vs Ref Eoc Ectrl Emeas fort eee mn S sets Ewe to the initial potential E This potential value can be set in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Eve controlled potential Ear or measured potential E meas Notice that only the last point of this period is recorded at the time 0 e Pulse waveform Scan Ewe from E to E V vs Ref Eoc Ei defines the vertex potential as E either in absolute vs Ref or versus Eg or Ei with pulses height Py mV p
77. aked cee aneaes a ees Sees 79 2 6 Ohmic Drop Determination seereis pne e E E E EE 80 2 6 1 MIR manual IR compensation n nannannannannannnnnnnnnnnnnnnnnnnrnrrnrrrrrnrrnrrarrnrrnernrrnernerner 80 202 ARAR COMPEMSaUON WITE O sansa S 80 209 Ck 8 L A 1g 60 ena a 81 Electrochemical applicat ons ssostni a eeieeans 83 3 1 BANO e E E EEE 83 3 1 1 PCGA Potentiodynamic Cycling with Galvanostatic Acceleration c 0 ccceee 83 3 1 1 1 Description of a potentiodynaMic SEQUENCE cccceeeeeeeceeeeeeeseeeseeeeeeeeeeees 85 3 1 1 2 Description of the cell characteristics window for batteries ccceeeseeeee ee 87 SUS POGA Data Processing ise etic erie sete E a hae esse ees 88 3 1 1 3 1 Compact function 88 3 1 1 3 2 Intercalation coefficient determination 89 3 1 2 GCPL Galvanostatic Cycling with Potential Limitation cccceccsseeeeeeeeeeeeseees 90 3 1 2 1 Description of a galvanostatic SCQUENCE cceeeeeeeeeee eee eeeeeeeee eee eeeeeeeeeaeeeees 92 S122 PADDICAUOMosresternsrtactinc reliant E E cinta dete a 94 3123 GGPL Data DIOCCSSING ici siiesicienctcicishietdaientadiccn E 95 3 1 2 3 1 Compacting process for the apparent resistance determination 95 3 1 3 GCPL2 Galvanostatic Cycling with Potential Limitation 2 ccccccceeceeeeeeeeeeeees 95 3 1 4 GCPL3 Galvanostatic Cycling with Potential Limitation 3 cceccceeccseeeeeeeeeeees 97 3 1 5 GCPL4 Galvanostatic Cycl
78. al Defines the recording conditions These values can be entered simultaneously The first condition that is reached determines the recording A zero value disables the recording for each criterion Until Eye lt Ey o V AQ to AQy MA h lt gt AXy vee fixes the limit of the working electrode potential Ewe to a maximum value if I gt 0 or to a minimum value if lt 0 and the charge from the beginning of the sequence AQ Ax for the whole step The maximum charge can be entered into mA h AQy or as a normalized charge related to intercalation electrodes Axy Once a limit is reached the experiment proceeds to the next step Rest even if the programmed time ty is not terminated These limits can be bypassed by entering O values into the controls Note when the AQy Ax limit is reached the E test is skipped This is due to the fact that the AQy limit is considered as the maximal charge that can be applied to the battery during the discharge Once reached the experiment must go to the next sequence e Report to the GCPL technique chapter for more information on the other blocks Caution Applying a constant power during a discharge experiment corresponds to an increase of the current in absolute when the potential decreases The user must be careful to note the final current of the first constant power step For example let s consider a 30 watts power discharge applied to a battery with a 10 A booster We
79. al Control Electrochemical Applications Batteries Testing FE Corrosion F Custom Applications Polarization Resistance PA Stepwise Potential Fast Chronoamperometry SPFC P Staircase Els L a roy application au Insert Technique Load from default Custom Applications oJ W Advanced setting r Cell charactenstics Rename aer Famen Cancel Fig 161 Custom application section in the technique window In this example two custom applications have been created Anodic stripping voltammetry and RDE rotating speed effect In the bottom of the technique window a frame with three buttons is dedicated to the custom applications The selected custom application can be renamed or removed The user can also add a custom application with the Add button Special applications For each special application it is possible to stop the experiment with an external limit such as a temperature a speed In the Config menu select External Device and select Other in Device Type this window is displayed in the Fig 162 To record external analog signals through the auxiliary DB9 connector The user has to configure Analog In1 and or Analog In2 inputs to record external signals Our instruments can control and record analog signals from 10 to 10 V Most of the external devices work into a 0 to 5 V range The user has to define the conversion between the input voltage and the variable to plot in the activated frame It is
80. al injury Guarantee and _ liability claims in the event of injury or material damage are excluded when they are the result of one of the following Improper use of the device Improper installation operation or maintenance of the device Operating the device when the safety and protective devices are defective and or inoperable Non observance of the instructions in the manual with regard to transport storage installation Unauthorised structural alterations to the device Unauthorised modifications to the system settings Inadequate monitoring of device components subject to wear Improperly executed and unauthorised repairs Unauthorised opening of the device or its components Catastrophic events due to the effect of foreign bodies ONLY QUALIFIED PERSONNEL should operate or service this equipment Techniques and Applications Manual Table of contents 1 2 Equipment installation General description Intended use of the equipment Instructions for use General safety considerations IV BEVUN CUS FLU so seesaw eee ee nace eee tne ener eterncestn este csesecasuensecsevecurgocs ine niassecncumucenasevecsee 4 Electrochemical Techniques seciessicescececcccrwscsceseweasweseweascesewcnswecewecsvestweaswesewecavenweccweceeiaatens 5 2 1 Voltamperometric techniques cccccceccceccceeceeeceeccceeceueceueceueseusseeeseeeseeeseeeseessaeees 5 Zila OCV OPerOrcCuUt VOtaJE oiron 5 2al 2 VOCV
81. alized Corrosion technique 140 Techniques and Applications Manual 3 3 6 1 Description all oio 500 Wvs Ref o o 5 BE 4 4 4 dE dt 100 p 7 600 0 me JEN 500 py Fig 127 Detailed diagram of the Generalized Corrosion technique e First step rest potential or open circuit sequence Rest for tp eee MN a S fixes a defined time duration tp for recording the rest potential or until dE dt lt dEp dt mV h gives the user the ability to shorten the open circuit period at the time when the decay of the potential is lower than a given value Record Ewe with dEp mV resolution and atleast every dtg S allows the user to record the working electrode potential whenever the change in the potential is gt dER or every dtp time interval Data recording with dEr resolution reduces the number of experimental points without loosing any interesting changes in potential When there is no potential change only points according to the dtg value are recorded but if there is a sharp peak in potential the rate of the potential recording is governed by the potential recording resolution e Second step potential scan Scan Ewe with dE dt mV s 141 Techniques and Applications Manual defines the potential scan The software selects the smallest potential step according to the control potential resolution defined in the Advanced settings window see the EC
82. ammetry SWV c ccccccsseccseececeeeecseeeeseeeesseeeeseueesseeeeseeeessaeeeseneessaeeesees 53 Staircase galvano Impedance SGEIS ccc cecccceececeeeeeeeeeceeeesseeeeseeeeseeeeeseeeessneeeseeesaaees 42 Staircase Potentio Impedance SPEIS ccceccccsececeeseeseeeeceeceeseeeeseuseseueeeseusesseeesseeesaaees 45 staircase Votammet y SV Fenica ana AN 23 25 Stepwise Potential Fast Chronoamperometry SPFC cccceccsececeeeceeeceeeseeeseeseeseeeees 175 Techniques and Applications Manual A ONG EREE E sachet Saeed EEE feel sce sack ate EEA TAA EEE T 19 23 68 72 131 190 Technique LINK ON ccs xats cits naa cicas oxxnetes Suusd des beantsais Seusd ves benatsue Suse des beaut Sumne aes Shade oad baat des aaaE Ma eee 194 Temperature Control Unit TOW cciceverctines deceit ceria tecedt ster Seaed ace Rioters a aN 150 MEIC GIS ar a a a E E 73 Variable Amplitude Sinusoidal microPolarization VASP ccccseeceeeeeseeeeeeeeeeeeeseeesaeeees 137 Wallerin a cantante cantenenaiel ns 74 EN SUO at aa cans cre nes en attire cet eek Bes ac Bice try et nok E NES SR NORA NEC eRe Cine 40 Zero Resistance Ammeter ZRA cccccscccsccceccceccceccceecceeeceecceeccseccseecaeecaeecaeecaeecaeseeeenass 167 Zero Voltage CUIMENI ZV GS assietetetssecoteacte dla thwcetensbehinddiecetesbinladdiesaladdiesdndebereladdecd nds 169 214
83. ammetry Aavanced GVA uurre r a 11 13 Depassivation Potential Dep POU sasvsswcacarsedelp axnewiacuaaeds a aaa Raa RAR 146 Differential Normal Pulse Voltammetry DNPV cccceccseeeseeeneeeseeeneeeneeseeeseeeseeeneeenseenes 55 Differential Pulse Amperometry DPA ccccccseccseceneeeneeeseeeneeeneeeseeeseeeseeeseeeseeeseeeneeeneeenes 61 Differential Pulse Voltammetry DPV ccccccscccsccceeeceeeceeeceeeceeceeeceeecseeceeesseeseeesseeseeenes 50 Eor Ss UME EVD oaas errr eae ere ee a ee eee ee 131 ExtemalDEvce Conto a ED Cas fatale ap asccclas eh sediggnsan cisco aco asics saps dace aces vane ga 77 Galvanostatic Cycling with Potential Limitation GCOPL cc ceeeeeeeeeeeeeeeeeeeeeeeeeeeens 90 104 Galvanostatic Cycling with Potential Limitation 2 GOPL2 cc ceccccccceececeeeeeeeetaneeeeeeeaes 95 Galvanostatic Cycling with Potential Limitation 3 GCPL3 cc eecccccccececeeeeseeeseeeeseeeeaes 97 Galvanostatic Cycling with Potential Limitation 4 GCOPLA cc ceccceecceeeeneeeseneeseeeeaes 98 Galvanostatic Cycling with Potential Limitation 5 GOPLO5 cc ececeeeecseeeeseeeeeeeeeseeeeenees 100 Galvanostatic Impedance GEIS srci a e a e a a 35 40 80 Generalized Corrosion GC c ccccccseccceeececeeeeceeeeeceueeceecesseeeeseusessueeeseueeseeesseeeseneesseeeesens 139 Impedance SIE EO 1e EET E E E ET E EE TEET pate sts TE T E EAEE EAE TT 42 MpSdaNC E rasna E A anno emadena
84. amplitude and duration defined by the user During the potential sweep the potentiostat measures the current resulting from electrochemical reactions consecutive to the applied potential The cyclic voltammogram is a current response as a function of the applied potential Contrary to the cyclic voltammetry the potential steps are not as small as possible but adjusted exactly to the user s convenience Begin Set Initial Potential to E Potential Sweep to E Reverse Potential Sweep to EY 2 Repeat ng times Reverse Potential Sweep to 5g End Fig 14 General diagram for Staircase Voltammetry 23 Techniques and Applications Manual This technique is similar to the usual cyclic voltammetry but using significant digital potential staircase i e it runs defined potential increment regular in time The technique is composed of e astarting potential setting block a 1 potential sweep with a final limit E4 a 2 potential sweep in the opposite direction with a final limit Es the possibility to repeat n times the 1 and the 2 potential sweeps a final conditional scan reverse to the previous one with its own limit Er Note that all the different sweeps have the same scan rate absolute value The detailed diagram on the following figure is made of three blocks pet Ewe ta Ej 0 000 YO y3 Eoc Scan E we with dE 1 000 rity perdt 0 0100 Reverse scan to vertex E gt 1 000 WO yE
85. ance measurements in galvano mode by applying a sinus around a current The impedance measurement is repeated on each current step 42 Techniques and Applications Manual Fig 34 SGEIS description diagram The detailed diagram is made of three blocks that can be separated into five parts e single or multi sine mode e initial current e waiting period before EIS frequency scan with recording conditions and current scan with number of current steps definition show frequencies gt gt mio oo sf scar di 20 000 m Fig 35 SGEIS detailed diagram 43 Techniques and Applications Manual e Initial current Scan from A vs lt None gt Ictrl Imeas to A vs lt None gt lli With N current steps sets the initial current to a fixed value lt none gt or relatively to the previous controlled current letn measured current lmeas sets the final current to a fixed value lt none gt or relatively to the previous current User defines the number of steps between and Hh e Waiting period before EIS Before EIS wait for t Lee MN erui S O Record every dE mV and dt sS before the EIS measurement the user can apply an equilibration period with the ability to record the current During this period no impedance measurement is done e Impedance scan Scan from fi MHz kHz Hz mHz yHz to f MHz kHz Hz mHz y
86. and it is the current of the full stack But the voltage of the stack in series is the sum of the voltage of each element of the stack The slave channels are used to measure the voltage of each element The master channel controls the full stack Of course to do that a current booster or a load box must be coupled to the master channel When launching the EC lab software if a multichannel system is detected the opening window will propose to create a New Stack experiment or to Load a Stack Setting No esperiment loaded on curent channel To create an expenment please select one of the following actions Hew wm Load Settings mw New Stack O Load Stack Settings Fig 176 Experiment selection When clicking on one of these choices the following window appears for channels selection 199 Techniques and Applications Manual master CHS CAZ Refl slave CH5 Refi Group Synchronize Stack Set stack mode for the channels slave CH3 Rete slave CH5 1 2 oe E 4 WIS WIG iF oes 9 10 WIT 12 slave CH5 Refs 13 14 15 16 slave CHE Ref Select all Stack master q 3 p Number of mesured elementsin 4 10 gt me aes slave CHE Ref slave CHE OE Cancel slave CHE Refa master CHS CA1 Refs Ref Fig 177 Channel selection window for Stack measurements Thanks to the description on the right the user will have to select the master channel and the slaves The user must have in mind tha
87. ar or logarithm spacing For example a scan from fi 100 kHz to f 1 kHz with Ng 5 points per decade in logarithm spacing will perform measures at the following frequencies in kHz 100 63 1 39 8 25 1 15 8 10 6 31 3 98 2 51 1 58 1 and a scan from fi 100 kHz to f 1kHz with N 11 total number of points in linear spacing will make measures at these following frequencies Hz 100 90 80 70 60 50 40 30 20 10 1 Click on the Show frequencies gt gt button to display the list of the scanned frequencies Note it is not possible to select Ng points per decade in linear spacing with an amplitude V mV sets the sinus amplitude to Va Equivalence with Vams is also given Note the following relationships between Va Vpp and Vams Va Vpp2 and Vams Vop 2 2 Wait for py period before each frequency measurement offers the possibility to add a delay before the measurement at each frequency This delay is defined as a part of the period Of course for low frequencies the delay may be long average N mesure s per frequency repeats N measure s and average the values for each frequency Non stationary correction drift correction corrects the drift of the system This feature is more specially dedicated to low frequencies Note 1 If this option is selected the sinus frequencies are evaluated over 2 periods instead of 1 increasing the acquisition time by a factor of 2 2 In the bottom
88. arization ccccccccseeeceeeeeeeeeeeeeeeeaneeeaeeeesaaees 143 3 9 9 DED FOl DEPaSsIVallon Potential ansianct ansuecsnonnasiexcascatsuanmderemangatessennnctexemaceibaannds 146 3 3 9 CPT Critical Pitting TeMperature cccccccccssececeeeeseeeeeceecesseeeensesensueesseesensaees 149 3 3 9 1 Differences in the CPT technique between the VMP and the other MSKUMENIS cece ccdecetetivetsceseedebeneieeebeatiecsbeniee lated a a abe ccedesieteieds 149 3 3 9 2 MINISTAT Thermostat Cryostat circulating bath cccccceseesseeeeseeeeseees 150 3 3 9 3 TCU Temperature Control Unit only for the VMP cceeecceeeeeeeeeeeee ees 150 I3 9A ORT TSCHINGUC sccscccsctes ees tees N a 152 395900 CGRPRT2 ecdesia teketonte ee cee eee ictaseb ets 157 3 3 10 MPP Multielectrode Potentiodynamic Pitting ccccceecseeeeseeeeeeeeseeeeseeeaes 161 3 3 10 1 DCSCHO UO crire A a ene gaeeteee eeu ada 163 3 3 10 2 Wala PROCCSSING aieea 165 3 3 11 MPSP Multielectrode Potentiostatic Pitting cccccccsseccseseseeeeseeesaeeeseeeeaes 165 3 3 12 ZRA Zero Resistance AMMetel ccccccccsecceecceeeceeeceeceeeseeeceeseeeseeeseeeseeees 167 S313 ZVG Zero Voltage Curent csscsictsvecdinsacct E E RRE ENEE 169 3 4 Custom APDIICAIUGN S ean aa 171 3 4 1 MUIC Measurement of U I Correlations cccccceccccseceeceeeeceeeeeseeeeseeesaeeeeseaees 171 3 4 2 PR Polarization Resistance nannannannannannnnnnnnennn
89. around the corrosion potential or measurement of the charge transfer resistance Ra Rp is defined as the slope of the potential current density curve at the free corrosion potential Rp AE AT ae gt o In this application the determination of Rp and leor is made only with three or four potential steps The detailed diagram is made of five blocks Initial open circuit voltage Potential step s Open circuit voltage Reverse potential step s Repeat 171 Techniques and Applications Manual Begin Evie n 2 2 steps reverse steps be E Ba loat jat initial AE CY ocyv J a thy Aat o oa t End Fig 153 Polarization Resistance general diagram Repeat all ng D timels Fig 154 Polarization Resistance detailed diagram 172 Techniques and Applications Manual e Initial open circuit voltage The open circuit voltage is the standard block so report to the OCV technique chapter for more information e Potential step s From E Apply n potential step s with AE mV Keep potential level s for At s or until dl dt lt A s applies n potential steps with AE amplitude and At duration from the potential of the previous OCV period E If the current variation is small dl dt lt dl dt limit then the step is shortened Set the dl dt limit to 0 to cancel the test Do recording n times per potential level duration define
90. ast every dtg S allows the user to record the working electrode potential whenever the change in the potential is gt dEr or every dtr time interval Data recording with dEr resolution reduces the number of experimental points without losing any interesting changes in potential When there is no potential change only points according to the dt value are recorded but if there is a sharp peak in potential the rate of the potential recording is governed by the potential recording resolution e Second step potential scan Scan Ewe with dE dt mV s defines the potential scan The software selects the smallest potential step according to the control potential resolution defined in the Advanced settings window see the corresponding section in the EC Lab software manual for more details From Ei V vs Ref Eoc Ectrl Emeas to E V vs Ref Eoc Ei from a potential E defined in absolute vs Ref the reference electrode potential or versus a previous open circuit potential Eoc previous controlled potential Een or previous measured potential Emeas to Ep value defined in absolute or versus Eg or Ei Record lt I gt over the last of the step duration averaged N voltage steps every dl pA nA pA mA A or dt S Two different recording conditions on the current are available with the potentiodynamic mode either recording an averaged current lt l gt on each p
91. at the control is done between the working and the reference electrode 211 Techniques and Applications Manual Index Alternating Current Voltammetry ACV cccccccccsecceseeeeceeceseeeeeseeeesseeeeseeseseeeesaeeeeseeeetaaeeees 28 aDParent TESISTAN CE Ri osne enei ound aE iea EAT TE TRETE 95 103 BIAGIO IAG amiee 39 Bode CIA GAN steak Gea Gert asi alate a Getta eG tise 38 Cell characteristics MIO IY ein oagedeaconandedseaeicendanqeessisnsscaxionaseesiaseuesednanseadsanecesatceaseanionese 89 Chronoamperometry CHrONOCOUIOMETIY ccccceececeeceeseeeeceeceeeeeeeseueeseeeeeseesesseeeesaeeeeaaees 16 GHTOMODOIENTIOMG IY s3iee st ctd cc enteai ted Sieh h E 20 Config Temperat O cenaa a en des Sina E O 152 Constant Amplitude Sinusoidal microPolarization CASP cccccccesseeeeeeeeseeeeseeeesseeeenees 138 Constant Current OSIO aropin atedei e e a a a a 129 Constant Load Diseara CLD jersi E E cians es ioe i aliearhti sitet 107 124 constant POWEE OPW asst cio i aaa eee aisle nei ain E 109 126 Constant Voltage SA ee ne ee nee eee en ee eee ee 127 GOPFOSIMeI Vy CMI srna E 133 Critical Pitting Temperature OP T derriere 149 Custom applications AOCAN ADPUIC AVON eren ee a tte Grae ec Gea te sie Gla ane cs Gra tee ott Ghat alts 178 CVA process dalare nanie cence cece nates cake EEE E EE E OO 14 Cyclic Potentiodynamic PIning CPP sansssasnsan aa 143 Cyclic V ltammetiy GW rrcsneiaa n a a GN 5 8 Gyclic Volt
92. aterials while using the compacting function report to the end of this section The quality of the determination is usually better than that obtained by derivation of a titration curve made with chronopotentiometry under galvanostatic mode because of the significant noise on the potential derivative with respect to the charge i e time 83 Techniques and Applications Manual J Parte wih Gober Acosar Nest Sweep DIEN ma T om s End To Ns Potential Swep with Galvanostatic Acceleration t f Rest Rest Potential Sequence Test Ewe vs E imit Next Sweep or go ne times to sequence Ms End Fig 78 General diagram of the PCGA application 84 Techniques and Applications Manual 3 Test Eweve EL go to 1 4 Gobacktoseg Ngt 0 RB enk feohaigusi for Mig lo imela JEPARA BE Fig 79 Detailed diagram of a PCGA sweep 3 1 1 1 Description of a potentiodynamic sequence See Fig 79 e First step stepwise potentiodynamic sweep Scan Ewe with dE mV per dt h naan mn S fixes the potential scan rate choosing the step amplitude dE and its duration dts independently According to the control potential resolution it might be necessary to adjust the experiment limit to have exactly the desired potential step amplitude The default resolution is near 300 uV for the SP 150 VSp VMP3 technology and 333uV for the SP 200 300 technology For example this resol
93. atic current range with pulsed techniques The resolution of each range is different and dynamic current range changes may lead to spikes on the plot DNPV recorded and calculated variables The variables below are stored in the DNPV raw files MPR state byte time s control V 7 EwelV lt l gt mA Q Q mA h And the next variables are calculated from lt I gt or the potential to save size on disk forward mA lt l gt values at the end of the pulses lp reverse mA lt I gt values before the pulses lbp delta pA difference between lt I gt values before and at the end of the pulse I lbp E step V step potential value resulting from the potential sweep and used to plot the current 2 3 4 NPV Normal Pulse Voltammetry Pulsed techniques have been introduced to increase the ratio between the faradic and nonfaradic currents in order to permit a quantification of a species to very low concentration levels The Normal Pulse Voltammetry is one of the first pulsed techniques elaborated for polarography needs An essential idea behind the NPV is the cyclic renewal of the diffusion layer With a DME this is achieved by the stirring accompanying the fall of the mercury drop But at other electrodes renewal may not be so easily accomplished NPV consists of a series of pulses of linear increasing amplitude from E to Ey The potential pulse is ended by a return to the base value E The usual pr
94. b software user s manual for more details on the potential resolution adjustment I Range and Bandwidth fixes the current range and bandwidth for this experiment e Second step open circuit period with monitoring of the electrode potentials turn to Rest for tp Msema mn Ss fixes a maximum time tr to stay in open circuit mode or until dE dt lt dER dt mV h gives the user the ability to shorten the open circuit period when the decay of the potential is lower than a given value Record every dEr mV and at least every dtg Ss allows the user to record the working electrode potential with a given potential resolution whenever the change in the working electrode potential is gt dEr or and at least every dtp time interval Note the conditional test if tz O0 which bypasses the open circuit period e Third step test on the final open circuit potential test Eel gt lt EL eee eT V The test is performed with the conditional value gt if the open circuit period just before the test occurs after a charge I gt 0 and with the conditional value lt after a discharge I lt 0 106 Techniques and Applications Manual lf the condition is not fulfilled the above 3 steps will be repeated until the working electrode potential reaches the final open circuit condition Eye gt E after a charge or Ewe lt E after a discharge Note the user is allowed to
95. changing cycling conditions To do so the user must loop to a previous sequence sweep Ns Ns lt Ns and repeat the loop ne times note that the number of such cycles will be n 1 Skipping to the next sequence sweep or line is obtained by setting n to O A usual technique consists of a first sequence sweep Ns 0 of open circuit potential then a second sequence sweep Ns 1 of charge then a third sequence sweep Ns 2 of discharge and finally a loop on the second sequence sweep Ns 1 for a given time To skip directly from a controlled current potential period mode to the next sequence without an open circuit period the user must set the open circuit period to O t 0 The end of the technique is obtained when Ns and n take O values in the last sequence sweep It is also possible to force the end of the technique by setting Ns to 9999 at any sequence sweep PCGA Potentiodynamic Cycling with Galvanostatic Acceleration This application corresponds to electrode cycling under stepwise potentiodynamic mode The user is allowed to define the potential sweep by setting the potential step amplitude and duration It is also possible to go to the next potential step before the duration which has ended if the charge or discharge currents are lower than a given value while stille cycling with a minimum galvanostatic rate This is a direct technique for determination of the incremental capacities dx dV of insertion electrode m
96. cial linear fit is applied to extract the semi conductor parameters E we t Fig 36 SPEIS description diagram The potential of the working electrode follows the equation Eye E V sin 2 af t The detailed diagram is made of three blocks that can be separated into five parts e single or multi sine mode e initial potential e waiting period before EIS frequency scan with recording conditions and potential sweep with definition of the number of potential steps 45 Techniques and Applications Manual m I dm Ph OO 000 kHz Show frequencies gt gt B Booo 25 0 0 oio fo 7 lj 4 D 7 F r scan dE 0 050 Fig 37 SPEIS detailed diagram e Initial potential Scan Ewe from E V vs previous Ref Eoc Ectrl Emeas to E V vs previous Ref Eoc Ei With N potential steps sets the initial potential to a fixed value E vs Ref the reference electrode potential or relatively to the previous OCV potential Eoc controlled potential Eet measured potential Emeas sets final potential to a fixed value E vs Ref the reference electrode potential or relatively to the previous OCV potential Eo 46 Techniques and Applications Manual initial potential Ej The number of potential steps is defined by user with the N value e Waiting period before EIS Before EIS wait for t Ai nena MN S O Record every dl mV and
97. controlled in this application between Refi and Ref3 in the standard connection mode The first metal must be connected to Ref1 CA2 leads and the other metal must be connected to Ref38 CA1 leads Ref2 is connected to the reference electrode It could be necessary to connect the ground lead if the signal is noisy 167 Techniques and Applications Manual Begin Note 1 for the VMP this technique is not available for channel board versions C0247XX03U WC and C0247XX03W_GND 1997 1998 delivery Note 2 for the ZRA technique the recording of Ese vs Ever IS forced into the data file The ZRA technique is made of 4 blocks Initial OCV e e OCV e Repeat End They are detailed below Fig 149 ZRA general diagram 0 hE m ooo 0000 mAh 7 m Don mAh 7 4 Goto 2 ne lo timels Limit to QT p 000 mh Fig 150 ZRA detailed diagram 168 Techniques and Applications Manual e Initial OCV The open circuit voltage is the standard block so report to the OCV technique chapter for more information e ZRA Start ZRA for ti oiis MN eee S applies 0 V between the working electrode WE and the counter electrode CE for ti time or until I gt Im pA A after tp Ss limits the ZRA duration if the current becomes greater than Im This test is performed only tp seconds after the beginning of the ZRA block to avoid exiting on the current perturbation that may occur when
98. cuit period will be the average potential of the working electrodes These electrodes will be disconnected one by one as and when they reach their pitting current e Third step rest potential or open circuit sequence See the first step for more details about the open circuit period e Fourth step potential sweep with threshold pitting detection sequence Scan E with dE dt mV mn Fixes the scan rate dE dt in mV mn The software adjusts the potential step amplitude and its duration From Ei V vs Ref Eoc Ectrl Emeas to E V vs Ref Eoc Ei 148 Techniques and Applications Manual from a potential E defined in absolute vs Ref the reference electrode potential or versus a previous open circuit potential Eoc previous controlled potential Een or previous measured potential Emeas to Ep value defined in absolute or versus Eg or Ei Record e lt I gt over the last Of the step duration averaged N voltage steps el every dl HA or dt S Two different recording conditions on current are available with the potentiodynamic mode either recording an averaged current lt l gt on each potential step or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ Until I gt lp pA A after t S fixes the threshold pitting current Ip to detect Setting of a blanking time t eliminates a
99. detailed diagram e Pulsed Galvano Charge Set l to pA A for ty ere mn S Set l to pA A for to hw mn S define the pulse currents values and durations With I Range and Bandwidth fixes the current range and the bandwidth for this experiment Repeat for at most t h mn S sets the pulse period duration If t is set to zero then l and t and na are not used and the current l is applied for t duration 115 Techniques and Applications Manual on I Keep Ewe between Emin V and Emax V limits the WE potential on I current steps and limit AQ 2 dQ dQ2 to AQy mA h limits the total charge of the galvano pulse for current sequence to AQvy Record Ewe once over n I alternances and over n sequences limits the recordings with dE and dt resolutions one l l alternation for na if t gt 0 and one sequence for ns Zero values bypass the na and n limitations with resolution dE mV and at least every dt S On l l gt alternation multiple of na and sequence multiple of ns record one point each time the potential variation from previously recorded value is superior to dE and time dt These recording conditions can be set separately or together The first condition reached determines the recording A zero value cancels the recording condi
100. diagram is made of five blocks e Initial Open Circuit e Applied E period e Applied E gt period e Open Circuit a They are detailed below End Fig 158 SPFC general diagram 175 Techniques and Applications Manual Fig 159 SPFC detailed diagram e Initial Open Circuit This is the standard OCV block without the dEp dt test Therefore report to the OCV section for more details e Applied E period Apply E4 V for t4 naain sS sets the potential to E4 for t duration E Range enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range and Bandwidth sets the Range and Bandwidth for the entire experiment Record lt l gt every dt S records points every dt time e Applied E period 176 3 4 4 Techniques and Applications Manual Apply Ez V for to 05 Ss applies a second potential step E gt in the same way than the first step with different parameters Record lt l gt every dt S records points every dtz time e Open Circuit reports to the OCV technique for more details e Repeat Repeat n time s repeats the E Es and OCV blocks n times A value of n 0 cancels the loop PEISW Potentio Electrochemical Impedance Spectroscopy Wait
101. ding is gt dQ and or every dt time interval Limit AQ to AQy mA h lt gt AXy fixes the maximum charge change from the beginning of this sequence during the sequence This charge is equivalent to a Axy quantity which corresponds to a normalized charge related to intercalation electrodes e Second step open circuit period with monitoring of the electrode potentials turn to Rest for tp Patas Mn s fixes a maximum time tp to stay in open circuit mode or until dEwe dt lt dEp dt mV h gives the user the ability to shorten the open circuit period when the decay of the potential is lower than a given value Record Ewe every dEp mV and at least every dtg sS allows the user to record the working electrode potential with a given potential resolution whenever the change in the working electrode potential is gt dEr or and at least every dtp time interval Note the conditional test if tz O0 which bypasses the open circuit period 92 Techniques and Applications Manual e Third step test on the final open circuit potential test Ewe gt lt E V The test is performed with the conditional value gt if the open circuit period just before the test occurs after a charge I gt 0 and with the conditional value lt after a discharge I lt 0 If the condition is not fulfilled the above 3 steps will be repeated until the working electrode potent
102. dwidth enables the user to select the current range and the bandwidth damping factor of the potentiostat regulation e Final potential Reverse scan yes or no towards Ep V vs Ref Eoc Ei give the possibility to end the potential sweep or to run a final sweep with a limit Er Option Force E E While the experiment is running clicking on this button allows the user to stop the potential scan set the instantaneous running potential Ewe to E or Es according to the scan direction and start the reverse scan Thus E and or E 2 are modified and adjusted in order to reduce the potential range Clicking on this button is equivalent to click on the Modify button Enter the running potential as E or Es and validate the changed parameters with the accept button This button 20 Techniques and Applications Manual allows the user to perform the operation faster when the limit potentials have not been properly estimated and to continue the scan without damage to the cell Note it is highly recommended to adjust the potential resolution according to the experiment potential limit This will considerably reduce the noise level and increase the plot quality Graph tool Generate cycles See the cyclic voltammetry technique for more details 2 1 8 LASV Large Amplitude Sinusoidal Voltammetry Large Amplitude Sinusoidal Voltammeiry LASV is an electrochemical technique where the potential excitation of the working el
103. e The highly qualified staff will be glad to help you Please keep information on the following at hand Description of the error the error message mpr file picture of setting or any other useful information and of the context in which the error occurred Try to remember all steps you had performed immediately before the error occurred The more information on the actual situation you can provide the easier it is to track the problem The serial number of the device located on the rear panel device Bio Logic SAS Model VMP3 s n 0001 Power 110 240 Vac 50 60 Hz Fuses 10 AF Pmax 650 W www bio logic info CAUTION CE DO NOT OPEN ATTENTION RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR The software and hardware version you are currently using On the Help menu click About The displayed dialog box shows the version numbers The operating system on the connected computer The connection mode Ethernet LAN USB between computer and instrument G eneral safety considerations o Class WARRANTY The instrument is safety ground to the Earth through the protective conductor of the AC power cable Use only the power cord supplied with the instrument and designed for the good current rating 10 A max and be sure to connect it to a power source provided with protective earth contact Any interruption of the protective earth grounding conductor outside the instrument could result in person
104. e is made of five blocks it is also possible to display the column diagram Fig 4 Techniques and Applications Manual Eoc Eoc foo Bo fo asvi2ev v F r 4000 points per cycle Repeat n lo timels 0 000 aE e End Fig 3 Cyclic Voltammetry detailed flow diagram i 0 000 dE vt 100 ph 75 0 ms Force E E2 JEN 1 0 mi 4000 points per cycle Fig 4 Cyclic Voltammetry detailed column diagram Techniques and Applications Manual e Starting potential Set Ewe to Ej V vs Ref Eoc Ectrl Emeas sets the starting potential in absolute vs Ref the reference electrode potential in the cell or according to the previous open circuit potential Esc or controlled potential Eet or Measured potential Emeas e First potential sweep with measurement and data recording conditions Scan Ewe with dE dt mV s 300 uV 15 ms allows the user to set the scan rate in mV s The potential step height and its duration are optimized by the software in order to be as close as possible to an analogic scan Between brackets the potential step height and the duration are displayed according to the potential resolution defined by the user in the Advanced Settings window see the corresponding section in the EC Lab software manual to vertex potential E V vs Ref Eoc Ei fixes the first vertex potential value in absolute vs Ref or accord
105. e After options Example of linked experiment Let us program the following experiment that could be used for a Levich plot 1 Trigger In wait for a trigger to start 2 MP mode 0 OCV period 5 s mode 2 potential sweep from 0 V to 1 V with 10 mV s 3 Wait 1 s with modification of the RRDE rotation speed no recording 4 Loop to MP technique five times To build the experiment click on Modify and select New experiment on the right click menu In the technique selection window choose TI Trigger In The instrument will wait for a trigger to start On the parameter settings window right click with the mouse Select insert new technique Choose the Modular potentio technique and click Ok check that the technique will be inserted after the trigger Report to section 2 4 2 page 68 for more details about the Modular Potentio technique For sequence N 0 select mode 0 OCV and for sequence N 1 select mode 2 potential sweep and set parameters for every sequence To add a wait and a loop technique repeat the same operation insert new technique and set parameters The wait technique with RRDE control is described in Fig 66 of section 2 4 4 page 74 For the loop option choose goto technique 2 MP for 5 times and report to the section 2 4 8 page 77 for more details Then click on the Accept button This will send the experiment list and the experiment parameters to the instrument Note that the current
106. e current or charge limit is reached If the limit is reached the loop condition go to Ns for n times if set is not used and the program continues to the next sequence N 1 The AQ value is the integral charge for the current sequence This value is not reset if there is a loop on the same sequence Ns N 0 values disable the tests 2 Recording conditions Record every dl pA A dQ fA h A h pC kKC and dt S lt I gt every dts sS Techniques and Applications Manual you can record either an instantaneous current value or an averaged current value lt I gt The recording conditions during the potential step depend on the chosen current variable For the instantaneous current the recording values can be entered simultaneously Then it is the first condition reached that determines the recording A zero value disables the recording for each criterion For the averaged current the user defines the time for the average calculation In that case the data points are recorded in the channel board memory every 200 us for the VMP2 VMP3 VSP SP 150 SP 50 BiStat and the SP 300 SP 200 HCPs and CLB 500 and 20 ms for the VMP and the MPG Leave dl alone for Chronoamperometry experiments and dQ for Chronocoulometry experiments enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the p
107. e different possibilities for trigger in and out stop start stop LAL Ie f IL b ib g Table 1 Triggers in and out IL AisingEdge Rising Edge Falling Edge Walt for a trigger with Send a trigger with Rising Edge tigger duration tq E h Do mA oon Oo Fig 64 Trigger In and Out The trigger In option puts the instrument in a waiting configuration until it receives a trigger with rising edge or falling edge depending on the instrument that generates the trigger signal The trigger Out option sends a trigger to an external instrument with a rising edge or falling edge before or after a technique It is possible to select the duration of the Trigger Out Inserting the trigger before or after the technique will start or stop the run These features can be set for every technique of the experiment The triggers are available on the DB9 connector as described below Ground Ext TIL out Fig 65 DB9 Pin assignment 73 Techniques and Applications Manual A special cable made with a DB9 connector on one side and 8 BNC plugs on the other side is provided with the instrument upon request 2 4 4 The Wait Option The Wait option has been designed for linked experiments This technique can be loaded only once another technique has been previously loaded Wait with previous controll forta D h jo mm Agomo or From technigue 1 begin untilthe fF month f3 day 2009 yea
108. e eels seen deeda sbi weeds eesetinse 37 2 2 4 2 Counter electrode EIS data plot cc cccccccccsecccseeeeeeeeeeeeeeeseesesseeeseeesseeees 39 2 2 4 3 Frequency VS time plot cccceccsecceeecceeceeeceeeccueceeeceueseusseueseeeseesseetseessaeess 40 2 2 5 Staircase Electrochemical Impedance Spectroscopy cccseeeeseeeeeseeeeeeeeeeeeeeees 42 2 2 9 1 SGEIS Staircase Galvano Electrochemical Impedance Spectroscopy 42 2 2 5 2 SPEIS Staircase Potentio Electrochemical Impedance Spectroscopy 45 2 2 0 2 1 Description 45 2 2 5 2 2 Application 48 2 3 PUSE Gienia R EER ER REEERE ER 50 2 3 1 DPV Differential Pulse Voltammetry cccccccceccceeeceeecececececeeeceeeseeeceeesseeseeenes 50 23 2 OWNV Sguar Wave Voltammetiy sirarna a R ETA RNA 53 2 3 3 DNPV Differential Normal Pulse Voltammetry cccccecceeeceeeseeeseeeseeeneeeneeenes 55 2 3 4 NPV Normal Pulse Volammetry ccccccccsccceeeseeeceeeseeeseeeseeseesseeseeeseeeneeeseeenes 57 2 3 5 RNPV Reverse Normal Pulse VOltaMMe try ccccccceecseeeceeeseeeneeeseeeneeeneeeneeenes 59 2 3 6 DPA Differential Pulse AMPerometry cccccccsecceeeceeecececeeecseeceeeseeeceeesseeseeenes 61 2 4 Tecnnigu S Bulder orenen 64 2 4 1 MG Modular Galvano siscivsccnsccvesetsandsavieewr sinh nasnenaaniwnarndjaadeaed oanredejoosasadauenenadaueneres 64 2 4 1 1 Open Circuit Voltage Mode 0 n nannnnnnnnnnunnnnnnnnnenn
109. e polarization resistance Rp is determined and plotted versus sinus amplitude A parametric identification is done on the curve to determine the corrosion current and corrosion coefficients This technique is only available on channel board with EIS ability Ewe Wa mar Ya mirn Time g Fig 122 Variable Amplitude Sinusoidal microPolarization technique Apply a sinusoidal potential modulation af joi He fom Ya min 100 my inne 7 0 m to Ya max 1000 m ime 70 71 mw with N 0 sinus amplitudes waitfor Pyy 0 00 period before each frequency average MN i Measure s per frequency drift correction Show Amplitudes gt gt ERange 2 24 fa PEAR Fade Range Auto 7 Bandwidth 5 step 10 0 rmi duration Tmn40s Fig 123 Detailed diagram of the Variable Amplitude Sinusoidal microPolarization technique 137 Techniques and Applications Manual Description e Apply a sinusoidal potential modulation at f MHz kHz Hz mHz uHz sets the frequency of the modulation applied to the cell From Va min mV to Va max mV sets the range of the sinus The equivalent value in MVays Is indicated With N sinus amplitude sets the number of the frequency applied between Va min and Va max Wait for Pw period before each frequency offers the possibility to add a delay before the measurement at each frequency This delay is defined as a part of the period At low freque
110. e potential always comes back to the initial potential The scan increment is defined by a pseudo Staircase made with steps of amplitude Py and duration Sr Notice that only one point is recorded at the end of the potential forward pulse and one point at the end of the potential reverse pulse making two points during the S period The settings above Fig 49 are given for a positive scan To perform a negative scan set E inferior to E and Sy to a negative value Scan rate mV s number of points these values are given as an indication and are calculated in the PC The scan rate is directly given by Py 0 00157 and the number of points is roughly 2 E Ei S for the forward scan average over the last of each step points selects the end part of the potential step for the current average lt I gt calculation to exclude the first points where the current may be disturbed by the step establishment A value of 60 Techniques and Applications Manual 100 will take all the step points for the average and a value of 0 will take only the last point Note that the current average lt I gt is recorded at the end of the potential step into the data file enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range Bandwidth sets the curre
111. e sequence goto Ns 1 will perform the next recording Ns 0 _ Ns 1 loop 0 Ns 1 loop 1 Ns 1 loop 2 lt Ew E pc AE i Fig 10 Chronoamperometry Chronocoulometry example 19 Techniques and Applications Manual Process chronocoulometry A process is associated with chronoamperometry chronocoulometry technique see figure below The variables that can be processed are the same as for the CV technique and the charge variation dQ chronocoulometry Process Data Input File C EC Lab DataS amples CA_Fe_1 mpr Load Processed File C EC Lab Data Samples 04 Fe 1_rompp Change Vanables To select from the input file To be added mode a J cycle number osred L Lo red hi ermar Q chargerm h control changes Q dichargemA h Ns changes l counter nc 1 time s control Ewe Lr All All Allow Reprocessing Cycles detinition auto Esport As Test Count half cycles Process Display Llose Fig 11 Chronoamperometry chronocoulometry processing window Note In this technique the first and last data points of each potential steps are not recorded automatically 2 1 6 CP Chronopotentiometry The Chronopotentiometry is a controlled current technique The current is controlled and the potential is the variable determined as a function of time The chronopotentiometry technique is similar to the Chronoamperometry Chronocoulometry technique potential ste
112. eas for at most t h mn S fixes the current value in absolute versus the previous controlled current previous sequence or versus the previous measured current and the maximum duration of the imposed current period The sign of the current value is for a discharge and for a charge when the positive electrode of the cell is connected to the working electrode cable red enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range and Bandwidth fixes the current range and bandwidth for this experiment 96 Techniques and Applications Manual Record Evye Ece every dE mV and at least every dt records one point each time Ewe Ece variation gt dE and time gt dt These recording conditions can be set separately or together The first condition that is reached decides the recording A zero value cancels the recording condition Until Ewe Ece gt Em V Limit Ewe lt Erv V Limit Ese gt Epc V Go to the next block if one condition is reached The tests depend on the l sign if l gt 0 and Ewe Ece gt Emor Ewe gt Ew Or Ese lt Ex then go to the next block OCV if l lt 0 and Ewe Ece lt Em or Ewe lt Ew or Ege gt Ere then go to the next block OCV Note the Ese test is reversed because
113. ecord Ece in the Cell characteristics window EIS measurement of the counter electrode is done and can be displayed Varables Representation Custom ki freg Hz a Reli hm 7 lm Ohm 7 1 Ohm Phaze deg timers Ewer M dls rn cycle number Phate ce deg cel Ohm Re 7ce Ohm 7 Imi cel 0hm F v Same selection for all files Frequencies v Hide Additional ariables 7 keep previous ares process keep previous zoom Cancel Fig 29 EIS variable selection window with WE and CE 39 Techniques and Applications Manual PES contre mpr Im Z vs Re Z s Im Zce vs Re Zce 0 025 0 02 0 015 0 01 0 005 0 005 Im Zce Ohm 0 01 0 015 0 02 0 025 0 03 0 04 0 06 0 08 0 1 0 12 Re Zce Ohm Fig 30 PEIS data curves with WE and CE recording 2 2 4 3 Frequency vs time plot It is possible to perform impedance measurements at different time intervals to follow the evolution of Z or Im Z Re Z phase Z versus time for each frequency value The user can repeat a PEIS impedance experiment where the potential E is fixed for a given time te for example 30 min After a run open the impedance file in a graphic window click on Selector and the file selection window appears figure below Then select time s for the X axis and choose the parameter you want to represent on Y1 axis Z in our example Note for a Z vs time plot the time variable
114. ectrode is a large amplitude sinusoidal waveform Similar to the cyclic voltammetry CV technique it gives qualitative and quantitative information on the redox processes In contrast to the CV the double layer capacitive current is not subject to sharp transitionsat reverse potentials As the electrochemical systems are non linear the current response exhibits higher order harmonics at large sinusoidal amplitudes Valuable information can be found from data analysis in the frequency domain Begin Set Initial Potential to E Set frequency Potential range definition from E to E End Fig 16 General diagram for Large Amplitude Sinusoidal Voltammetry This technique is similar to usual cyclic voltammetry but using a frequency to define the scan speed The curve of the potential excitation can be compared to a large amplitude sinusoidal waveform The technique is composed of e astarting potential setting block e a frequency definition fs e apotential range definition from E to Es e the possibility to repeat n times potential scan The detailed diagram on the following figure is made of two blocks 26 Techniques and Applications Manual SetEwe to Ej 0 000 YO yg Fiel Apply a sinusoidal potential scan with frequency Fe 0 100 Hz between vertes potential E4 0 000 WO yE Ret and vertex E gt 1 000 YO VE Fel Repeat ne m timels Record ever d o oo and di B0
115. ed as instantaneous values An automatic linear fit is performed around Esor to determine the polarization resistance R One R value is obtained for each sweep and the R evolution is plotted versus time on another graph The user can define the anodic and cathodic corrosion constants in the settings for more accurate calculations 3 3 3 1 Description Fig 120 Graphic description of the Corrosimetry application 134 Techniques and Applications Manual i 4 1 dE dt 100 p 5985 8 me JEM 500 py Fig 121 Detailed diagram of the Corrosimetry application e First step rest potential or open circuit sequence Rest for tp h uw MN a S fixes a defined time duration tp for recording the rest potential or until dEwe dt lt dEp dt mV h gives the user the ability to shorten the open circuit period at the time when the decay of the potential is lower than a given value Record Ewe with dEp mV resolution and at least every dtg sS allows the user to record the working electrode potential whenever the change in the potential is gt dEr or every dtr time interval 135 Techniques and Applications Manual Data recording with dEpr resolution reduces the number of experimental points without loosing any interesting changes in potential When there is no potential change only points according to the dt value are recorded but if there is a sharp peak in potential
116. ed value Emeas for ts duration Record e lt l gt every dt S el every dlp HA or dt S Two different recording conditions on a current are available with the potentiostatic mode either recording an averaged current lt I gt on given time duration or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ Until I gt Ip pA A after t Ss fixes the threshold pitting current Ip to detect Setting of a blanking time t eliminates a possible large peak of current when just applying the initial potential step in case of large AU value enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment Range bandwidth The current range depends on the Ip value and is automatically fixed The choice of the current range depends on the threshold pitting current value Ip and is automatically fixed The bandwidth is selected by the user The choice of the bandwidth is made by the user see the EC Lab software manual Upon detection of the pitting limit in current or if the time for the application of the potential has been reached the working electrode is disconnected In the case of a multi pitting experiment the applied potential after the open cir
117. eenee seas 30 Pe CIA AG TZU ONN e E E 122 Large Amplitude Sinusoidal Voltammetry LASV c ccccceecceeeeseeeeseeeeeeeeseeeeseeeseeeeseeesaeeess 26 LIC alr POlanIZAtION EI ciskssvatecadaut mandousracstas a seb eeancauetduatsemansauauaatsetieaats 132 Linear Sweep VoltammMetry LSV ccccsecccsecccseeceeeeceeeceuceceeecseeeceusecseeseusessueeseeessueesseesageess 16 Linked CXDSNIMENIS wicdsesss cicededtedeeediedeld pieced aa adele eelivediesebl ie a aa E 194 CUS o 9 8 21 8 fers 9 a nsn rete metas ta Meer tenet eet Senn sy ae eterna et ee ay oes ee me 194 ISOM OCH C ass alsa suis seiacayanmucmi snc esantanaycmisnr dant anmucmlsnrdanianaecantiareanlnauanuiaraanianies 194 WOW G ANCN geist rie date cc eet alse dace ioc cutee eth cena ot celsius eden 195 212 Techniques and Applications Manual WIG VEO IONS e3axtceet cc cast haart acess eet nach nee Sheets Sate ech tenes eet aed oN atch teh tt 195 RIONTCICK MIG spenen inde ncing tus pe a pE Aa ALE PEA PEREA RERE sna LER PEROT RARER DEGE RER 194 Linked experiments Settings sninsinerssiisie nsen a a e EN 198 LOOD aa a a a E E E E A cemmununiamaneei as Tf Manual tPoten tial GO Ol agg aitcosatns cccckansy aatars aerstani asain peeteatavciaanns doraant an neaes aemaee an eee 79 Measurement of U I Correlations MUIC ccccccccccceceececeeeeeseeeeseeeeeseeeeseeeessaeeesaeeesaeeeas 171 IIS eles ch ccen cee eters Steene tect ct tsutue eter A 150 Modular Galvano GalVaANOGy
118. ent variation dl and or charge variation dQ Range bandwidth The current range depends on lp and Im values and is automatically fixed The choice of the bandwidth is made by the user see the EC Lab software manual Once the threshold pitting current or the maximum temperature value is reached the working electrode is disconnected Afterwards the temperature is set back to the initial temperature Tj Lock the CPT2 technique Parameters of the CPT2 technique can be locked to prevent any user modification To proceed one must create the CPT2 setting file CPT2_lock mps in the same directory as the EC Lab software If the file CPT2_lock mps does not exist save your own set of CPT2 parameters into the file CPT2_lock mps button Save Set in the same directory than EC Lab Then the CPT2 technique will be locked when the next program starts To unlock the CPT2 technique move or rename the CPT2_lock mps stop and restart EC Lab this can be useful to modify the CPT2_lock mps file else the Load Set button is disabled 3 3 10 MPP Multielectrode Potentiodynamic Pitting Pitting corrosion occurs when discrete areas of a material undergo rapid attack while the vast majority of the surface remains virtually unaffected The basic requirement for pitting is the 161 Techniques and Applications Manual existence of a passive state for the material in the environment of interest Pitting of a g
119. entered simultaneously The first condition that is reached determines the recording A zero value disables the recording for each criterion Limit Ewe lt Ep V fixes the limit of the working electrode potential under charge discharge see warning 1 of GCPL technique This limit could be disabled by entering pass type p in the control Hold Ey once reached until I lt eee pA A next block on limit allows the user to stand at the potential Ey until the end of the sequence or until the current reaches a low limit value Im The limit In could be disabled by entering pass type p in the control Record every dq mA h dl pA A and dt defines the recording conditions during the potential period These values can be entered simultaneously The first condition that is reached determines the recording A zero value disables the recording for each criterion Limit I to Is when holding Ey return to Is on limit if the current I overhaul 1 in constant potential mode the system returns to constant current mode in order to protect the cell Limit the whole time to t EIET mn S defines the total sequence duration if not stopped on limits Limit AQ to AQy MA h lt gt AXy fixe the maximum charge change from the beginning of this sequence during the sequence This charge is equivalent to a Axy quantity which corresponds to a normalized charge related to inte
120. ential in the cell or according to the previous open circuit potential Eoc or controlled potential Eet or Measured potential Emeas e Potential sweep with superimposition of sinusoid signal and measurement and data recording conditions Scan Ewe with dE dt mV s allows the user to set the scan rate in mV s The potential step height and its duration are optimized by the software in order to be as close as possible from an analogic scan to vertex potential E V vs Ref Eoc Ei fixes the first vertex potential value in absolute vs Ref or according to the previous open circuit potential Esc or previous potential Ej Add a sinusoidal signal to the potential scan With frequency fs kHz Hz mHz yHz And amplitude A mV defines the properties frequency and amplitude of the sinusoidal signal Reverse scan to vertex E V vs Ref Eoc Ei 29 Techniques and Applications Manual offers the possibility to do a reverse scan and to fixe the value of the vertex potential value in absolute vs Ref or according to the previous open circuit potential E e or previous potential Ej Repeat n times repeats the whole sequence n time s Note that the number of repeat does not count the first sequence if Ne 0 then the sequence will be done 1 time ne 1 the sequence will be done 2 times Nn 2 the sequence will be 3 times enables the user to select the potential range for adjusting the
121. ential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range bandwidth the current range depends on the Ip value and is automatically fixed The user makes the choice of the bandwidth Upon detection of the pitting limit in current or if the time for application of the potential has been reached the working electrode is disconnected In the case of multi pitting experiment the applied potential after the open circuit period will be the average potential of the working electrodes These electrodes will be disconnected one by one as and when they reach their pitting Current Data processing No data processing is available with the MPSP application 3 3 12 ZRA Zero Resistance Ammeter The Zero Resistance Ammeter is an application for the measurement of galvanic coupling current of dissimilar metals It is also made to perform some types of electrochemical noise measurement It consists of applying zero volts between the working electrode WE and the counter electrode CE and then measuring the current and the potentials Ewe Ece versus the reference electrode REF In most of the cases the coupling current is measured between two identical electrodes In real situations the electrodes are slightly different resulting in anodic behavior for one of them and cathodic behavior for the other one The potential is
122. erent limits can be applied and especially a limitation with the Analog Input 1 value 181 Techniques and Applications Manual Restfortp_ p ho ma 30 0000 Limit IdE we dtl lt dEp fdt Ewel lt Em pass mv for ty tb 0 00 3 Lim D opg Y Record even dEpR i oO rey o dtp 05000 3 Fig 164 Special Open Circuit Voltage Technique Rest for tp h mn S fixes a defined time duration tp for recording the rest potential or until dE dt lt dEp dt mvV h stops the rest sequence when the slope of the open circuit potential with time dER dt becomes lower than the set value value 0 invalidates the condition or until Eye lt Em mV for tp S stops the rest sequence when the potential of the working electrode reached Em during tp or until Analog In 1 Anolog In 2 lt gt Lim V for t stops the rest sequence when the limit defines in the Lim box is reached during tp Record Ewe every dEr mV resolution and at least every dtp S allows the user to record the working electrode potential whenever the change in the potential is gt dEr with a minimum recording period in time dtr Data recording with dEr resolution can reduce the number of experimental points without loosing any interesting changes in potential When there is no potential change only points according to the dtr value are recorded but if there is a sharp peak in potential the rate of recording increases 3 5 2 SMP Special
123. ery dl pA A dQ fA h A h pC kC and dt lt I gt every dts sS you can record either an instantaneous current value or an averaged current value lt l gt The recording conditions during the potential step depend on the chosen current variable For the instantaneous current the recording values can be entered simultaneously Then it is the first condition reached that determines the recording A zero value disables the recording for each criterion For the averaged current the user defines the time for the average calculation In that case the data points are recorded in the channel board memory every 200 us for the VMP2 VMP3 VSP SP 150 BiStat and the SP 300 and 20 ms for the VMP and the MPG Leave dl alone for Chronoamperometry experiments and dQ for Chronocoulometry experiments enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment range bandwidth enables the user to select the current range and the bandwidth damping factor of the potentiostat regulation e Loop goto Ns for nc time s allows the experiment to loop to a previous line Ns lt N for n times The number of loops starts while the loop block is reached For example on N 3 if one enters goto Ns 2 for nN 1 time the sequence N 2 N 3 will be e
124. es and Applications Manual The 4 points method gives more accuracy so it is proposed by default Nevertheless it is not always possible to make a reduction after an oxidation so then chose the 3 points method Note one can perform more than the 4 points and 3 points method with the Polarization Resistance technique but the process here accepts only these two If several points have been recorded per potential steps n gt 1 it is possible to exclude some points for the calculus For example selecting Calculate lt I gt for point 3 to 10 will exclude the first two points Chose the R unit Q cm or Q and click on Compute to calculate the next values e e e e R R Bc a a kK 4 3 and R os __Eaitioie anodic L A cathodic i _ l averaged 2 3 L n ly l 3 points method IL n with r lt and r gt 4r 3r h l Li 4 points method with e i being the potential and the average ii 4i i current without excluded points on the potential step AE e2 i2 on 2AE 3 i3 on AE or 3AE according to the selected method and e4 14 2AE Note if there are several loops n gt 0 then the e i values are averaged on the different loops before the calculus 3 4 3 SPFC Stepwise Potential Fast Chronoamperometry The Stepwise Potential Fast Chronoamperometry Begin is a simple technique designed to loop on two n potential steps Initial Open Circuit 4pplied E1 period The
125. es of the table in graphic software in order to have a Ragone plot see figure below 10 Power W 0 i L i i ji i i 1 2 2 5 3 3 5 4 Energy W h Fig 103 Ragone plot for a Li ion cell 1 35 A h 113 Techniques and Applications Manual 3 1 10 APGC Alternate Pulse Galvano Cycling The Alternate Pulse Galvano Cycling experiment has been designed to perform fast galvano steps between two values I and l with special recording conditions This gives the ability to follow fast phenomena on long periods The diagram is made of four blocks that can be linked with a parameters table Pulsed Galvano Charge Rest Potential Sequence Test Ewe vs EL Next sequence ON AB De oo oo ToWs Pulsed Galvano Charge Rest Potential Sequence Test Ewe vs E L Nest Sequence or go ne times to sequence Me Hez u mio 2 td om oF te Fig 104 APGC general diagram Similar to the other battery experiments the first sequence N 0 is forced to OCV and the other sequences are executed one after one with the possibility to loop to a previous experiment number from the third sequence N 2 The detailed diagram is described below 114 Techniques and Applications Manual oo co o m 3 000 4200 o oo hon po o Falla 3 If Ewel EL pas W goto 1 Go back to sequence NM lo RGIS VATS facta for ng lo times ETAY ABST auf Fig 105 APGC
126. esolution adjustment Range Bandwidth sets the current range and bandwidth values for the whole experiment Non stationary correction drift correction corrects the drift of the system This feature is more especially dedicated to low frequencies Note if this option is selected the sinus frequencies are evaluated over 2 periods instead of 1 increasing the acquisition time by a factor of 2 e Current scan with number of current steps definition 44 Techniques and Applications Manual Scan I to A vs lt none gt Ictrl Imeas With N current steps dl mA defines the current scan limit to in either absolute or versus the previous controlled or measured current The user selects the number of current steps from to and the step amplitude dl is displayed as information Note It is possible to modify on line the settings of an impedance measurement during the experiment The user can Modify Pause Resume or Stop the experiment while it s running 2 2 5 2 SPEIS Staircase Potentio Electrochemical Impedance Spectroscopy 2 2 5 2 1 Description The SPEIS technique consists of a staircase potential sweep potential limits and number of steps defined by the user An impedance measurement with an adjustable number of frequencies is performed on each potential step For all these applications a Mott Schottky plot 1 C vs Ewe or 1 C vs Ewe can be displayed and a spe
127. esulting from electrochemical reactions consecutive to the applied potential The cyclic voltammogram is a current response as a function of the applied potential Traditionally this technique is performed using a straight analog ramp Due to the digital nature of the potentiostat however the actual ramp applied consists of a series of small potential steps that approximate the linear ramp desired see the control potential resolution part in the EC Lab software manual Begin Set Initial Potential to E Potential Sweep to AL Reverse Potential Sweep to EL Repeat n times Reverse Potential Sweep to EL End Fig 2 General diagram for Cyclic Voltammetry The Cyclic Voltammetry technique has been briefly detailed in the EC Lab software manual This technique corresponds to normal cyclic voltammetry using a digital potential Staircase e it runs defined potential increment regular in time The software adjusts the potential step to be as small as possible The technique is composed of e astarting potential setting block a 1 potential sweep with a final limit E4 a 2 potential sweep in the opposite direction with a final limit Es the possibility to repeat n times the 1 and the 2 potential sweeps a final conditional scan reverse to the previous one with its own limit Er Note that all the different sweeps have the same scan rate absolute value The detailed flow diagram on the following figur
128. et to a fixed value E or relatively to the last rest potential E lt oc gt or the last controlled potential Epc Techniques and Applications Manual co T7OAB ae oo End t to Ns or Wes moiamro md oo Next Sequence 7 or go ne times to sequence Ms End 5 Fig 8 Chronoamperometry Chronocoulometry general diagram The detailed diagram is composed of two blocks e potential step e loop 17 Techniques and Applications Manual Apply Ej 0350 V vs Ref l for ty E h o mn 10 000 0 Limita l max pass m Imin pass m AO AOM A000 mAh Record even dl S000 p dg A000 mAh hal dt 11000 E Range 25V 25V fa renin Aa ri Range Auto Bandwidth 7 Gobackto sequence Ns p PRT RTE AAYAR A fo ng p timels EAV rasa eer A Hs 0 Fig 9 Chronoamperometry Chronocoulometry detailed diagram and table e Potential step with data recording conditions 1 Potential step Apply E V vs Ref Eoc Ectrl Emeas the potential step is defined in absolute vs Ref the reference electrode potential or according to the previous open circuit potential Eoc controlled potential Eet or measured potential Emeas for i aaan M eenn MN nanana S fixes the potential step duration limit I to Imax pA A and AQ lt AQy fA h A h pC kKC lain sieves pA A curtails the step duration if th
129. evious controlled potential Een or previous measured potential Emeas to Ep value difined in absolute or versus E or Ei Hold E for tp Maserin mn or until I gt h mA for t gt tg S And mA reached but no longer than t S after I gt h Hold the potential to E for t time or until the critical pitting condition is reached The condition is first defined by and ty If the current remains higher than the preset value during the time tg than the CPT is reached If it doesn t this condition can but does not have to pass be followed by a second condition set by l and t If the current continues to rise and reaches the value of l within a time t te includes ty so must be gt ty then again the condition for pitting is reached Fig 139 illustrate these conditions Record lt I gt over the last of the step duration averaged N voltage steps every dlp HA or dt S Two different recording conditions on a current are available with the potentiodynamic mode either recording an averaged current lt l gt on each potential step or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolu
130. experiment Range is automatically set according to and l values Rp fit parameters dE mV Ba MV BoF mV allows the user to select the potential window around Egor for the R fit and to set corrosion coefficients previously determined by a Tafel Fit e Third step rest potential or open circuit sequence reports to the first step for more details about the OCV period e Fourth step repeat sequence Repeat n time s The potential sweep described in the second step will be repeated n times Contrary to the MPP technique no current limitation is available with the linear polarization application 3 3 3 2 Applications of the Corrosimetry application When the experiment is running EC Lab software displays the polarization curve vs Ewe on a first graph and the processed value R versus time on a second graph leor and Ecor are also calculated in the processed file mpp and can be displayed in real time on the second graph 136 Techniques and Applications Manual 3 3 4 VASP Variable Amplitude Sinusoidal microPolarization This technique is a non linear EIS technique and can only be used for systems with tafelian behavior it is used as a corrosion technique to determine the corrosion current and corrosion coefficients In this technique a potential sinusoidal wave is applied around the corrosion potential Ecorr with N amplitudes increasing from Va min and Va max At each amplitude th
131. experiment number is now displayed for the 4 pages Advanced Settings Cell Characteristics Parameters Settings and Linked Experiments Note that one can accept all the experiment parameters at the end Once in modify mode one cannot change the current experiment number 195 4 3 Techniques and Applications Manual Advanced Settings OY 0 Cell Mode Potentiostatic 1 Characteristics O Potentiodynanic 2 SetEweto Es 0 000 ys Ret forte 0 hio mn 00000 Parameters m 1 Tl a rere n Dimite imar e me oe 4 Loop Imin pass md ADI gt ADW 0 000 mah Record lt l gt ever dt 0 100 0 2 E Ranges 24 24 ha m Arena PT Range Auto Bandwidth z Go back to sequence Ng p RGIS aos OARA for ne f times ETAY eer Fig 173 Linked experiment parameter setting window The linked techniques are displayed on the left of the window with their number in the experiment Click on the button corresponding to the technique you want to see to display the detailed diagram Note it is possible with the technique linker to apply 50 ms OCV period between two techniques reduced to 0 6 ms if the previous technique is an OCV The user has just to activate Turn to OCV between techniques in the advanced settings window Click on the Run button to run the acquisition The program will then ask for a file name that will be used for all the linked experiments wi
132. fer to the relevant maintenance documentation must do adjustments maintenance or repair EQUIPMENT MODIFICATION To avoid introducing safety hazards never install non standard parts in the equipment or make any unauthorised modification To maintain safety always return the equipment to Bio Logic SAS for service and repair GUARANTEE Guarantee and liability claims in the event of injury or material damage are excluded when they are the result of one of the following Improper use of the device Improper installation operation or maintenance of the device Operating the device when the safety and protective devices are defective and or inoperable Non observance of the instructions in the manual with regard to transport storage installation Unauthorized structural alterations to the device Unauthorized modifications to the system settings Inadequate monitoring of device components subject to wear Improperly executed and unauthorized repairs Unauthorized opening of the device or its components Catastrophic events due to the effect of foreign bodies IN CASE OF PROBLEM Information on your hardware and software configuration is necessary to analyze and finally solve the problem you encounter lf you have any questions or if any problem occurs that is not mentioned in this document please contact your local retailer list available following the link Erreur Reference de lien hypertexte non valid
133. g Z Ohm log Z versus log f and Z phase versus log f for the impedance 1 10 100 1 000 10 000 100 000 freq Hz log spacing log Y versus log f and Y phase versus log f for the admittance On the first figure log Z and log Y have been overlaid on the same graph On the second one Phase Z and Phase Y have been overlaid Phase Z deg 1 10 100 1 000 10 000 100 000 freq Hz log spacing Fig 26 BODE diagrams for both impedance blue and admittance red e Nyquist diagram The Nyquist diagram is the plot of Im Z Ohm Im Z versus Re Z for impedance Im Y versus Re Y for admittance The main difference between both visualizations is that the admittance diagram better shows the high frequency semi circle Im O hm 1 With the Nyquist visualization the axes are automatically displayed proportionally 0 005 0 01 0 015 0 02 Re Ohm 1 Fig 27 NYQUIST diagrams for both impedance blue and admittance red 38 Techniques and Applications Manual e Black Diagram The Black diagram is the plot of log Z versus phase Z for impedance log Y versus phase Y for admittance O 6 0 8 1 as bo log Ohm mm fa log Z 0 hm mo I bh I Ja bh 24 20 Phase Zydeg Phase Yyideg Fig 28 BLACK diagrams for both impedance blue and admittance red 2 2 4 2 Counter electrode EIS data plot When the user selects R
134. he last of each step points selects the end part of the potential step for the current average lt I gt calculation to exclude the first points where the current may be disturbed by the step establishment A value of 62 Techniques and Applications Manual 100 will take all the step points for the average and a value of 0 will take only the last point Note that the current average lt I gt is recorded at the end of the potential step into the data file enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range Bandwidth sets the current range and bandwidth values for the whole experiment Note It is highly recommended to not use the automatic current range with pulsed techniques The resolution of each range is different and dynamic current range changes may lead to have spikes on the plot DPA recorded and calculated variables The variables below are stored into the DPA raw files MPR State byte time s control V g Ewe V lt l gt mA Q Q mA h And the next variables are calculated from lt I gt or from the potential to save size on disk forward mA lt l gt values at the end of the pulses lp reverse mA lt I gt values before the pulses lbp delta pA difference between lt l gt values before a
135. he number of points per cycle is displayed into the diagram enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range bandwidth enables the user to select the current range and the bandwidth damping factor of the potentiostat regulation 2 1 5 Chrono I Q Chronoamperometry Chronocoulometry The basis of the controlled potential techniques is the measurement of the current response to an applied potential step Chronoamperometry involves stepping the potential of the working electrode from an initial potential at which no faradic reaction generally occurs to a potential E at which no electroactive species exist at the beginning of the experiment The current time response reflects the change in the concentration gradient in the vicinity of the surface Chronoamperometry is often used for measuring the diffusion coefficient of electroactive species or the surface area of the working electrode This technique can also be applied to the study of electrode processes mechanisms An alternative and very useful mode for recording the electrochemical response is to integrate the current so that one obtains the charge passed as a function of time This is the chronocoulometric mode that is particularly used for measuring the quantity of adsorbed reactants The potential steps can be s
136. he table is executed at each loop of the experiment beginning to Ns 0 The external device parameters can be hold during a defined duration before each step Set control to 5 on External Device and wait with previous control fortg 0 h g ma fo V Record even dE 0 00 mi di po mA dt 0 0100 s E Range 254 254 a Greaney Aa E i Ha 0 Fig 70 External Device Control parameters O Set control to one can configure the external device using the link External devices menu Config External devices The recordings are optional Record every dE mV dl pA A and dt s chooses one or several optional recording conditions enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment The EDC technique has a parameters table in the parameters settings window which can be related to the sequences selection 2 4 8 The Loop option As with the Wait option the loop option has been designed for linked experiments This technique can be loaded only when another technique has been previously loaded Goto technique Ne i for mp HO times Fig 71 Loop technique This option goes to a previous technique loaded in the experiment and can repeat this operation several times 11 Techniques and Applications Manual Note that it is possib
137. he user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range Bandwidth sets the current range and bandwidth values for the whole experiment 3 4 5 How to add a homemade experiment to the custom applications EC Lab software offers the user the ability to create his own applications and save it as a Custom Application This new application built by the user is made with several linked techniques The procedure to create linked experiments is described in the following section When the experiment is built the user can save it in the custom applications Right click on the mouse and select Save as Custom applications or in the experiment menu select Save as Custom applications An experiment saved as custom application appears now in the custom application section of the technique window in blue The blue color is used like for the user s reference electrode to distinguish the standard EC Lab applications from the customer applications The custom applications are available only for a new experiment not when one or several techniques are already loaded 178 3 5 Techniques and Applications Manual Insert Techniques Electrochemical Techniques FP Voltamperometic Techniques FP Impedance Spectroscopy FP Pulsed Techniques aA Technique Builder E gt Manu
138. hivuteablencivbivaaath 172 Potentio Electrochemical Impedance Spectroscopy Wait PEISW ccccceeeseeeeeeeeeees 177 Potentiodynamic Cycling with Galvanostatic Acceleration PCGA cc sccccseceeeeeseeeeeeees 83 POteniiOstalle Impedance PEIS 5 2325 ical oiieeleteetel a techie A 32 Pe CONGINO MMM Gurri inna catia Glam arate h tee Gra saree erate L en Chater et Gat 5 68 181 Process Constant Power Technique Summary ccccceccceecceceeeeceeeeeseeeeseeeesseeeeseeeesaaeeeseeeetsneeeas 113 M hl Pittina Statisties ainnise a Deri lStineS a a eee Sune Deeded 165 Polanzaton ROSiStant Gresser a E E 173 POCOS SA Terran ce oe neem ee ee ea ea ee 9 Process data YC CSI Eae cette hecet venta tettekeceevetatmetekeceteatatutte ccete ratte hccette katate keceete ctu 9 Processing GIIFOMOGCOUIOIMIGURY araea nna eecic ead cdtdeaid ca enolase beatae a sehet 20 GMFOMODOIERIOIMOIY sonsonen toas osetia iosie A O 23 COPR a eR te ae nen ee RSS me EE Re Ne MEN EE Ne EMT eRe oe 95 Reverse Normal Pulse Voltammetry RNPV ccccsccceeeseeeseeeseeeseeeseeeseeeneeseeeseeeneeeneeenas 59 Rolalng electrode gnerien a ree eee 153 Special Galvanostatic Cycling with Potential Limitation GCPL cecccseeeeseeeeeeeeeeeees 190 special Modular Potentio MP vrccstscresdceneteticstoen cieartelniecsatindunstelvdelstelelsuateesiadearledavareeeiadeed 182 special Open Circuit Voltage OGV 2cseuniie teenie heen eee 181 Square Wave Volt
139. hniques and Applications Manual Begin Il gt lp End Fig 147 General diagram of the Potentiostatic Pitting application Fig 148 Detailed diagram of the Potentiostatic Pitting application e First step standard open circuit sequence previously described with conditional duration and choice of recording resolution e Second step potentiostatic period with pitting limit for the current Apply E v vs Ref Eoc Ectrl Emeas during ti A wiaseaewe mn Ss sets the potential directly vs Ref the reference electrode potential or with respect to the final rest potential value E or previous controlled potential Eg or previous measured value Emeas for ti duration Record e lt l gt every dt S 166 Techniques and Applications Manual o every dl HA or dt S Two different recording conditions on the current are available with the potentiostatic mode either recording an averaged current lt l gt on given time duration or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ Until I gt lp pA A after t S fixes the threshold pitting current Ip to detect Setting of a blanking time t eliminates a possible large peak of current when just applying the initial potential step in case of large AU value enables the user to select the pot
140. hole open circuit period or the whole galvanostatic sequence This point is taken at the time corresponding to the end of the period sequence Once selected it calculates the ohmic drop Ri at the end of the galvanostatic sequences and the ohmic drop at the end of the rest periods Then the name of the compacted processed file is filename channel_cR mpp in the case where Ri is the only one processed variable Ri ve time 18650 _GITT 170604 1 cRompp i Ewe vs time 18650 _GITT_170604_1 mpr Ewe V T 20 000 40 000 60 O00 time s Fig 88 Ri determination red circles after a GITT experiment blue crosses obtained with an 18650 Li ion battery 3 1 3 GCPL2 Galvanostatic Cycling with Potential Limitation 2 The GCPL2 application is similar to the GCPL one but has been designed to limit both the working electrode WE and the counter electrode CE potential and it does not hold the cell potential after the current charge discharge The GCPL2 technique is made of 4 blocks e QGalvanostatic e OCV e Potential test e Loop This is detailed below 95 Techniques and Applications Manual o o Z t o 4 foo s00 3 000 M man acco foo E i S 4 I E E ass goto 1 Go back to seg Ne lo OGG eat Heaney for My lo tmel A aay nagar Fig 89 GCPL2 detailed diagram e Galvanostatic period Set I to Is pA A vs lt None gt Ictrl Im
141. ial reaches the final open circuit condition Eye E after a charge or Ewe lt E after a discharge Note the user is allowed to bypass this test by entering p pass instead of a voltage value e Fourth step conditional test which proposes to go to the next sequence or to loop on a previous sequence Ns Ns lt Ns lf ns is set to 0 then the technique executes the next sequence If the user wants to loop to a previous sequence line he has to fill the 2 last columns of the table Go to Ns and n cycles The end of the technique is obtained by setting Ns and n to 0 in the last sequence or setting Goto sequence Ng 9999 at any sequence which then will be the last one executed even if the next sequence has its settings Such a complete sequence corresponds to one line of the table This line is composed of the columns which represent the successive variables encountered when setting the diagram the current range and the loop conditions all parameters which must be set by the user see Warning 2 Note that it is always possible to force the end of a technique while it is running at any sequence sweep using the Modify button and setting Goto sequence Ng 9999 at the sequence one wants to stop The following table setting gives an example of the use of the loop conditions 1 0 0 1 000 3 000 0 1 000 1 0 2 000 0 0 1 000 1 0 3 500 1 J 1 000 1 0 2 500 2 Fig 86 Example of loop conditions With these loop c
142. ies experiment with single sine measurement and the second part of the experiment at low frequencies with multisine measurement This will allow the user to Spare time e t is possible to modify on line the settings of an impedance measurement during the experiment The user can Modify Pause Resume or Stop the experiment while running e The counter electrode potential can be recorded in EIS techniques So the EIS measurement is done simultaneously on the working electrode and on the counter electrode To do that select Record Ece in the Cell characteristics tab Nyquist and Bode diagrams can be plotted for both the WE and the CE electrodes The working and counter electrode variables are displayed respectively as follows with the additional extension Re Z and Re Zee Im Z and Im Zc_ 2 2 3 GEIS Galvanostatic Impedance This technique is very close to the Potentiostastic Impedance technique PEIS except that the current is controlled instead of the potential So report to the PEIS experiment section for more details 35 Techniques and Applications Manual Go back ta seq Ne E JORGE RTE AVANA form ff timejs Airne saguencei Increment cycle number lt Fig 23 GEIS diagram Note that the current can be applied vs the previous control current or the previous measured current previous sequence of a linked technique Instead of la one can consider the current peak to peak amplitude lpp related to
143. ig 132 Ministat Cryo thermostat The Ministat provides fast heating as well as cooling Moreover when the temperature rises above the requested temperature the Ministat switches automatically to cooling to provide rapid stabilization at the requested temperature setting The Ministat provides a security temperature control to be set manually to prevent exceeding the requested level for any circumstance The Ministat has been selected for the first CPT application and its parameters are stored within the software see next chapters but if more cooling liquid volume is needed one can provide a Cryo thermostat with higher capacity In the same way PT100 sensors can be provided with different diameter lengths and materials 3 3 9 3 TCU Temperature Control Unit only for the VMP The TCU is designed as an interface between the VMP and the Ministat The TCU generate a current signal that is calibrated for the temperature range of the Ministat 4 mA at 25 C 20 mA at 120 C This same signal can also be used to setup thermostats other than the Ministat The TCU also provides the readings of the PT100 thermocouple sensor in each of the individual electrochemical cells This data is then fed back into the proper VMP channel for further data processing This is done by connecting the Auxiliary input output connector from each VMP channel to the TCU input output connector seen in the picture below 150 Techniques and Applications Manual
144. ilable on the first sequence N 0 To select the current step type check the option box for ty Susi i OTEO MN eeeee S fixes the current step duration limit Ewe lt Em e eeeee mV and AQ lt AQny fA h A h pC KC curtails the step duration if the potential or charge limit is reached If the limit is reached the loop condition go to Ns for n times if set is not used and the program continues to the next sequence N 1 The AQ value is the integral charge for the current sequence This value is not reset if there is a loop on the same sequence Ns N 0 values disable the tests Record Ewe or lt Eye gt every dE mV and at least every dt S defines the recording conditions during the potential step O values disable the recording condition and the corresponding box stays green These values can be entered simultaneously and this is the first condition that is reached that determines the recording Range Bandwidth selects the current range and bandwidth values for the whole sequences e Loop goto sequence Ns for nc time s 22 Techniques and Applications Manual gives the ability to loop to a previous sequence Ns lt N for n times Sequences of the chronopotentiometry technique can be chained using the Table frame The first sequence is N 0 The number of loops starts while the loop block is reached For
145. ime and then every dE mV and at least every dt Ss allows the user to record the working electrode potential with two successive resolutions First the potential is recorded with a geometric time resolution in order to determine the apparent resistance with a process Secondly the potential is recorded with a given potential resolution whenever the change in the working electrode potential is gt dE or and at least every dt time interval 2 Potentiostatic period possible Limit Eye lt Ey V fixes the limit of the working electrode potential under charge discharge see warning 1 and stand for ty A assi mn s or until I lt P T pA A allows the user to stand at the potential Ey for a given time or until the current reaches a low limit value ly If the limit potential Ey is not reached within the time t or if ty is set to 0 the system skips to the next step Record AQ every dQ mA h and at least every dt S In the constant potential mode the system acts as a coulometer and a recording is performed every time the charge increment decrement since the previous recording is gt dQ and or every dt time interval 3 Safety limit for the cell Limit AQ to AQ y mA h lt gt AXp 2 00 fixes the maximum charge change from the beginning of this sequence during the sequence This charge is equivalent to a Axy quantity which corresponds to a normalized charge
146. ime ne 1 the sequence will be done 2 times Nn 2 the sequence will be 3 times Record the first cycle and every n cycle s offers the ability for the user to store only one cycle every n cycle in case of many cycles in the experiment The first cycle is always stored e Final potential Reverse scan yes or no towards Ep V vs Ref Eoc Ei gives the ability to end the potential sweep or to run a final sweep with a limit Er Hold E fort h mn s and record every dt S offers the possibility to hold the final potential for a given time and record data points during this holding period Options 1 Reverse While the experiment is running clicking on this button allows the user to reverse the potential scan direction instantaneously Contrary to the Force button the vertex potential is not replaced by the current potential value E and E gt are kept 2 Force E Ep While the experiment is running clicking on this button allows the user to stop the potential scan set the instantaneous running potential value Eye to E or Es according to the scan direction and start the reverse scan Thus E or and Es are modified and adjusted in order to reduce the potential range Clicking on this button is equivalent to click on the Modify button Enter the running potential as E or Es and validate the changed parameters with the accept button This button enables the user to perform the
147. ime n 1 the sequence will be done 2 times n 2 the sequence will be 3 times Process The polarization resistance files can be processed to calculate the Ry and leor values select Analysis Polarization Resistance to load the following window 173 Techniques and Applications Manual Polarization Resistance Process Eg File EM P Files PA mpr Load Settings n 2 AE 20 0 mom 10 i Apply a second set of potential steps s with reverse sign on AE electrode surface area 0 001 cir Options f Sports AE 2AE SAE Method i 4dponts AE 2AE AE 2AE 0 point i to point 10 fall the points Calculate lt I gt for C 2 cme Calculate A in p eo Outputs Linear Polarization resistance Ap anodic 9959 8 Compute Ap cathodic 9 9643 1 Copy Ap averaged 9961 45 Number of digits B leon 00135777 Close Fig 155 Polarization Resistance process Click on the Load button to select a polarization resistance file Then a summary of the parameters will be displayed into the settings frame Note that it is possible to modify the electrode surface area value for R in Q cm calculus here Then according to the experiment type it is possible to select the 4 points or the 3 points methods that both correspond to specific settings gt Fig 156 4 points method Fig 157 3 points method n 2 reverse steps n 3 do not reverse steps 174 Techniqu
148. ines are executed one after another Then an OCV potentiodynamic and OCV sequence for example will be programmed by 3 lines in the parameters table Setting n gt 0 will loop to a previous line Ns lt N for ne times 65 Techniques and Applications Manual Go to the battery protocols section 3 1 page 83 for more details on loops conditions It is possible to loop to Ns 0 but Ns must be lt N current sequence line number 2 4 1 2 Galvanostatic Mode 1 Hode AQI gt AQ Record every dE dtp dqp E Range Range Bandwidth Go back ta sequence Ma for My i OCW 0 Galyvanostatic 1 Galvanodynarmic 2 60 000 pA s lt None gt gt hA mn pooo 0 500 y oh cho n h 1 0 roi D5000 s 6 944 n h E 2 AW 250W Greaney Fea 100p4 E mediu 0 EGF emote facta 5 time s Ava reert SARA Ns 0 a a Fig 56 Modular Galvano Galvanostatic detailed diagram Set I to l pA A vs lt None gt Ictrl Imeas for t h Mn sets the current to a fixed value for t time The current value can be defined in absolute or versus a previous controlled current or measured current Limit Ewe to E V and AQ to AQy fA h A h pC kKC defines the potential and sequence charge limits The E limit is dependent on the charge sign the limit is Ewe gt EL if ls gt O Ewe lt E else To cancel the limits t
149. ing to the previous open circuit potential Eoc or according to the potential of the previous experiment E Measure lt I gt over the last of the step duration selects the end part of the potential step from 1 to 100 for the current average lt I gt calculation to possibly exclude the first points where the current may be disturbed by the step establishment Note that the current average lt I gt is recorded at the end of the potential step to the data file Record lt I gt averaged over N voltage step s averages N current values on N potential steps in order to reduce the data file size and smooth the trace The potential step between two recording points is indicated between brackets Once selected an estimation of the number of points per cycle is displayed in the diagram enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment ERange 25 254 Some potential ranges are defined by a default but the user can customize the Edit Potential Range E Range in agreement of his system by nnp E range min Yi max 1 000 iv clicking on Information on the resolution is given simultaneously to the change of minimum Defaut cance and maximum potentials resolution 50 pi range bandwidth enables the user to select the current
150. ing with Potential Limitation 4 ccceeccseeeeeeeeeees 98 3 1 6 GCPL5 Galvanostatic Cycling with Potential Limitation 5 ccccccceecesseeeeeeeees 100 3 1 6 1 Description of a galvanostatic SCQUENCE ccceececeeeeeeeeeeeeeeeeseeeeseeeeaeeens 102 O02 GGPES Data processing saci cits ns ee 103 LGS JADDOING AON sar a cancaaanaaniadanaeet a r 103 3 1 7 GCPL6 Galvanostatic Cycling with Potential Limitation 6 c ccccceecesseeeeeeeees 104 3 1 7 1 Description of a galvanostatic SEQUENCE cece cece cette ee eee eeeeaeeeeeaaeeeeenaes 105 31 8 CLD Constant Load DISchar Ge siseteccostacestarw es eu E sear eres 107 ILI SPW Constant POWE Ficia aese ae eucaiaiaamniaeesent 109 LLIT MV SS CIO ON Maite esis at ass vated astral anatiael saath aeaetnaadiael sath aeaelnawadialh dah aeaetnaMnaet castoas 109 3 1 9 2 Application of the CPW technique cceeceeeceeeeeeeeeeeeeeeeeeeeeesaeeeeeaeeeeeenees 111 3 1 10 APGC Alternate Pulse Galvano Cycling cccccceeeeeeeeeeeeeeeeeeeeeseeeeeeaeeeeeeaees 114 21 PPI Potentio Profile IMPOMAON sinara aa a 117 3 1 12 GPI Galvano Profile Importation recicu a a 119 3 1 13 RPI Resistance Profile Importation cccccceccssecseesenseeseseeseesenseesensensensees 120 3 1 14 PWPI Power Profile Importation ccccceccsecceeeceeeceeeseeeseeeseeeseeseesseeesaeees 120 3 2 FPHOLOVOIAICS PUSPOS S aiana 121 32A EV OhNaractenizaton IVO iere
151. ing with potential limitation 3 GCPL3 battery testing technique similar to the GCPL2 with the ability to hold the working electrode potential after the galvanostatic phase Galvanostatic cycling with potential limitation 4 GCPL4 battery testing technique similar to the GCPL with a global time limitation for the charge discharge period Galvanostatic impedance GEIS technique for impedance measurement in galvanostatic mode Generalized corrosion GC technique used to study general corrosion It consists of half a cycle or a cycle of usual cyclic voltammetry with a digital potential sweep range current range used in the experiment It is related to the current resolution 209 Techniques and Applications Manual Impedance defined by the ratio E I IR compensation in the electrochemical cell the resistance between the working and the reference electrode produces a potential drop that keeps the working electrode from being at the controlled potential IR compensation allows the user to set a resistance value to compensate the solution resistance Linear polarization LP technique that consists of a potential ramp around the corrosion potential It is often used to determine polarization resistance and corrosion current Linked experiments EC Lab offers the ability to link up to ten different experiments with the technique linker Linked experiment settings the user can save the settings of linked experiments as a mp
152. introduction The second section describes electrochemical techniques and the third explains electrochemical applications The fourth part details how to build complex experiments as linked techniques It is assumed that the user is familiar with Microsoft Windows and knows how to use the mouse and keyboard to access the drop down menus WHEN A USER RECEIVES A NEW UNIT FROM THE FACTORY THE SOFTWARE AND FIRMWARE ARE INSTALLED AND UPGRADED THE INSTRUMENT IS READY TO BE USED IT DOES NOT NEED TO BE UPGRADED WE ADVISE THE USERS TO READ AT LEAST THE SECOND AND THIRD CHAPTERS OF THIS DOCUMENT BEFORE STARTING AN EXPERIMENT Techniques and Applications Manual 2 Electrochemical Techniques 2 1 Voltamperometric techniques 2 1 1 OCV Open Circuit Voltage The Open Circuit Voltage OCV consists of a period during which no potential or current is applied to the working electrode The cell is disconnected from the power amplifier On the cell the potential measurement is available Therefore the evolution of the rest potential can be recorded This period is commonly used as preconditioning time or for equilibration of the electrochemical cell Rest for tR 0 hig ma f300000 Limit IdEwe dt lt dEp dt Mo mh Record ever dep i D mi or dtp 0 5000 g E Range 25 2 5 rena Aa i Fig 1 Open Circuit Voltage Technique Rest for tp h mn S fixes a defined time duration tp for recording the rest potential or until dEwe d
153. ion Hold potential Reverse scan 143 Techniques and Applications Manual all foio aso 5 Bo dE fot 100 py 410 0 me JEM S00 ps Fig 129 CPP detailed diagram e First step rest potential or open circuit sequence Rest for tp h oe MN a S fixes a defined time duration tp for recording the rest potential or until dEwe dt lt dEp dt mV h gives the user the ability to shorten the open circuit period at the time when the decay of the potential is lower than a given value Record Ewe with dEp mV resolution and at least every dtr S allows the user to record the working electrode potential whenever the change in the potential is gt dEr or every dtg time interval Data recording with dEr resolution reduces the number of experimental points without losing any interesting changes in potential When there is no potential change only points according to the dtg value are recorded but if there is a sharp peak in potential the rate of the potential recording is governed by the potential recording resolution 144 Techniques and Applications Manual e Second step potential scan Scan Ewe with dE dt mvV s defines the potential scan The software selects the smallest potential step according to the control potential resolution defined in the Advanced settings window see the EC Lab software manual for more details From Ei V vs Ref Eoc
154. irst calibrate the temperature controls Select Config Temperature 157 Techniques and Applications Manual Rotating electrodes in the EC Lab main menu to load the next window Report to the CPT technique for more information Once the thermostat has been configured the CPT2 experiment can be loaded for a given channel in the same way as the other experiments the CPT2 technique is located in the Corrosion section of the EC Lab techniques The next figure shows the CPT2 diagram Begin ie Open Circuit Potential and apply initial temperature T Potential scan from E to E Scan temperature from T to T return to OC Set T back to LF Fig 140 General diagram of the CPT2 technique 158 Techniques and Applications Manual Se Ti hoog C Rest for tg 10 hi E mr Limit lt ldT dt lt 0 60 C lo h f mr Record ever dig 0 50 E dEg 1 my dtg E mr 5 00 g Keep T Tj ScanE we with dEfdt 200 000 mwe 4 0m 20 0 ms from Ey 200 V vs Ref v to Ep 700 vs Ref v Record js w over the last 50 of the step duration average H i voltage steps 7 4 0 m Keep Ewe Ef ScanT with dTfdt 20 00 Ce mn d p34 T de 02 8 from Ty to Te 50 00 LC Until I gt ip 10 000 p forty tn 1 00 or l gt Ip i m we Record sjy ay every dT 5 00 le dts 10 00 Range Bandwidth 5 medium Stop recording retum to CY and Se
155. ischarges mA h Counter irc dl dt rinats times control Eve lt 1 ma Al ir Average lo step Allow Reprocessing Cycles detinition Esport As Text Count half cycles Process Display Close Fig 5 Cyclic Voltammetry process window 2 Select on the variables to process 3 The process is finished when DONE appears 4 Click on Display to plot the processed file n has been added to the name of the processed file as an extension for the cycle number The other variables that can be processed in a CV experiment are the charge exchanged during the oxidation step Q charge and during the reduction step Q discharge and the total charge exchanged since the beginning of the experiment Q Q 10 Techniques and Applications Manual 2 1 3 CVA Cyclic Voltammetry Advanced The Cyclic Voltammeitry Advanced CVA is an advanced version of the standard CV technique report to the CV description part for more details about the technique This technique has been implemented to offer the user all the extended capabilities that can be required during a potential sweep In particular a table has been added to the CVA to link potential sweeps with different scan rates A vertex delay is possible at the beginning potential at both vertex potentials and the final potential For each of these delays the current and the potential can be recorded at the user s convenience A recording condition on cycles offers the possibility to
156. isk Electrode Control RDEC technique allows the user to control a rotating speed and change it during the experiment A direct link to the External Device window is done by clicking on the underlined words The RDEC technique contains a table then the user can link several RDEC sequences row Ns 0 to n Only one row of the table is executed at each loop of the experiment beginning to Ns 0 This tool allows the user to have for example an increase of the rotating soeed and to maintain during a defined duration this rotating speed before each step 19 Techniques and Applications Manual Set rotating speed to i ngg pm on External ADE and wait with previous control for tag m h E mA 10 amp Record every dE 0 00 mi di po mA dt p100 s E Range 265W 25W T m PTER RT RES 0 2 3 Fig 68 Rotating Disk Electrode Control O Set rotating speed to rpm one can set a temperature or the rotating electrodes speed if configured menu Config External devices The recordings are optional Record every dE mV dl pA A and dt s chooses one or several optional recording conditions enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment The RDEC technique has a parameters table in the parameters settings window which can be related to the se
157. iven material depends strongly upon the presence of an aggressive species in the environment and a sufficiently oxidizing potential This technique is designed to study pitting corrosion on one or several electrodes together in the electrochemical cell This technique corresponds to the pitting potential determination of a material using a potential sweep Begin Initial Rest Potential Sequence Potential Sweep with threshold pitting detection Disconnect the working electrode End I gt Ip Fig 143 General diagram of the Potentiodynamic Pitting technique First there is an open circuit sequence with recording of the working electrode potential for a given time or until its variation vs time is lower than a given limit Then the instrument applies a potential sweep starting either from the potential reached at the end of the open circuit sequence plus a possible offset or from a given value The potential sweep goes on until its limit or until the current reaches a value defined as the limit pitting current then the working electrode is disconnected For multi pitting i e if the same technique is applied on several channels in parallel the open circuit potential taken into account for applying the initial potential will be the average open circuit potential of the working electrodes The technique stops independently on each channel and the corresponding electrode is disconnected as soon as the pitting limit value of
158. le to apply a 50 ms OCV period between two techniques with linked techniques reduced to 0 6 ms if the previous technique is an OCV The user just has to activate Turn to OCV between techniques in the Advanced Settings window 2 4 9 The Pause technique 78 Pause Aa Jo Gea Saag ae aaa dea aah en Ane tle Se ey okt vo ee io eae Ae UTS Fig 72 Pause technique Once this technique is reached the experiment is turns into Pause mode The user must click on the resume button to continue the experiment In this case the instrument is in the OCV mode Techniques and Applications Manual 2 5 Manual Control 2 5 1 Potential Manual Control This application enables the user to directly control the working electrode potential using the mouse to move a Sliding index E mas 10 000 Cell Potential 0 0 000 Lo E min 10 000 Fig 73 Manual Potential Control It contains a sliding index 2 boxes for setting the lower and upper limits of the potential one box for the current potential value and the possibility to select the bandwidth Potential setting once you have selected this menu you can fix the potential limits and the controlled potential Then accept the settings Application of the potential to the cell this is performed by using the Run button If you have already set a potential in the intermediate box this potential is applied to the cell If not it will be the value corresponding to the index position
159. level at each frequency and then impedance measurement results tend to be noisier However increasing the level of excitation can bring to do impedance measurements in a non linear condition and then impedance results are not good To define the right excitation conditions the user has to know that in EC Lab software the maximum amplitude of the signal is defined as 0 5V and half of the I Range for Techniques and Applications Manual potentiostatic or galvanostatic mode measurement respectively Multisine measurements are done only for frequencies smaller that 1 Hz in the remainder of the frequency range only single sine measurement is available Note that if the frequency range defined by the user is included in the two kinds of measurement single sine and multisine the measurement will be done in continuity with first a single sine measurement and afterwards a multisine measurement Then with EC Lab software multisine measurements are faster than single sine ones by an order of 3 that is very interesting for systems with a rapid change Nevertheless definition of measurement conditions especially value of the excitation of the electrochemical cell has to be done in agreement with the preservation of a steady state regime of the system References Van Gheem E Vereecken J Schoukens J Pintelon R Guillaume P Verboven P and Pauwels L Electrochim Acta 49 2004 2919 2925 Pintelon R and Schoukens J System ide
160. limit is considered as the maximal charge that can be applied to the battery during the discharge Once reached the experiment must go to the next sequence Report to the GCPL technique chapter for more information on the other blocks 3 1 9 CPW Constant Power 3 1 9 1 Description The Constant Power application is designed to study the discharge eventually the charge of a cell at constant power The following figure presents the working electrode potential evolution vs time when the power stays constant P Ep Il limit Eva Fig 98 CPW discharge control P and measure Ewe sample vs time The constant power control is made by checking the current to maintain the E l constant The current increases when Ewe decreases 109 Techniques and Applications Manual f 7 o hfs mn foomo bo TE 15 000 0 Fig 99 CPW detailed diagram first step choice of the power value Set P E l uUW mW W for at most ty fier mn Ss sets the cell power to P E I for ty duration With gt 0 orl lt 0 and keep lt Iy pA A defines the charge I gt 0 or discharge I lt 0 mode and limits the current to a maximum value Im in order to preserve the cell and or the instrument With I Range and Bandwidth fixes the current range and bandwidth for this experiment Record every dE mV dq mA h and dt S 110 Techniques and Applications Manu
161. llow the voltage of each electrode versus a reference electrode in the battery 104 Techniques and Applications Manual 1 Setlto Ig 100 000 m WE lt None gt foratmostty ho hilo mn ooo00 Limit Ece gt Ey 4 300 Record even dE 00 m o dt 20000 3 Hold Eng forty 9 8 fio ma Oooo Limit I lt Im Hooo mA Record evey dQ 1000 mh o dtg 1 0000 Limit AG gt AQ 1 000 mah a57 AX 0 000 E Range 10 10 eae He a ade Range 100m Bandwidth 5 medium 2 RestfortR A hig mn foo000 Limit dE q dtl lt dEq_ dt joo mh Record even dER 00 m odtR ooog fete Gare faa A Gy go ae Ayi 3 lt Ecel lt EL pass y goto 1 4 Gobsack to seq Ms p POG a Hey for ip E imela JEPY S DARAS Ns o a Fig 95 Detailed diagram of one GCPL6 sequence 3 1 7 1 Description of a galvanostatic sequence e First step galvanostatic period that can be followed by a potentiostatic period 1 Galvanostatic period Set I to Is pA A vs lt None gt Ictrl Imeas for at most t h mn sS fixes the current value in absolute versus the previous controlled current previous sequence or versus the previous measured current and the maximum duration of the imposed current period The sign of the current value is for a discharge and for a 105 Techniques and Applications Manual charge when the p
162. ls file This allows the user to easily load all the experiment settings Loop technique available in the linked experiments and used to repeat one or more experiments It is different from the cycle in an experiment Manual Potential control application that enables the user to directly control the working electrode potential using the mouse to move a sliding index Modify button of EC Lab main window allowing the user to select a technique and change the experiment parameters before or during the experiment This button switches to Accept when the user clicks on Modular Galvano MG technique designed to perform a combination of OCV galvanostatic and galvanodynamic periods The user can link the MG sequences in the way he wants Modular potentio MP Technique designed to perform a combination of OCV potentiostatic and potentiodynamic periods The user can link the MP sequences how he wants This technique is very useful because it can be used to couple potential sweep detections with preconditioning steps either in OCV or at a particular potential Multielectrode potentiodynamic pitting MPP corrosion technique designed to study pitting corrosion on one or several electrodes together in the electrochemical cell This technique corresponds to the pitting potential determination of a material using a potential sweep Multielectrode potentiostatic pitting MPSP corrosion technique designed to study pitting corrosion on one o
163. m e Pulsed Resistance discharge Start discharge on R mOhms MOhms for t h nnn Mn S define the restance pulse value and duration Record Ewe every dE mV and at least every dts S limits the recordings conditions in voltage variation and or time variation I Range and Bandwidth fixes the current range and bandwidth for this experiment e Conditional test which proposes to go to the next sequence or to loop on a previous sequence Ns Ng lt Ns 3 1 14 PWPI Power Profile Importation This technique consists to apply various power values on a battery during a defined duration This technique is specially designed to fit with the urban driving patterns designed to test EV batteries The particularity of this technique is the large number of sequences available and the fact that the experimental settings can be defined by importation of a text file Note that experimental limits are not present in the setting it is highly recommended to use safety limits located in the Advanced Setting window to avoid overcharge or overdischarge of the batteries The text file importation columns are time s differential or absolute and power Waitt 120 3 2 Techniques and Applications Manual Set power to P 6 601 crite forts p hfj m Bm0 Record Ewe ever dE g 0 0 mi and at least every dtg 0 1 ooo Range 14 Bandwidth S medium Gobackto
164. m 29 vs Re 29 lm 10 vs Rei210 NS Im Z100 hm 0 04 Re Z10 Ohm peis 5 with R mpr lmi2stack vs Re 4 stack Im stack Ohm 0 6 Re stack Ohm Fig 178 Stack PEIS measurement with the master channel bottom and the slave channels top In this experiment 10 elements are studied in the stack of 15 Ni MH cells For this measurement one master channel and 5 slaves are necessary So the configuration is a 6 channels system 201 Techniques and Applications Manual GCPL6 mpr E vs time E vs time E3 vs time E4 ys time 1 500 time s GCPL6 mpr a Estack vs time Estack V 2 000 2 300 3 000 time s Fig 179 GCPL experiment on a stack of 15 cells bottom with only four elements studied top For stack experiments all the data points for the master and the slave channels are stored in a unique data file 202 Varnables Representation Custom ve Bode Impedance Nyquist Impedance Rel stac Black Impedance Imitat F ys t Rele UTERE slave Im 1 Bode stack slave Rel Bode Al Imp 2 cycle vs time Ref73ireq vs time Am 73 Ewel vs freq Re z4 l vs freq jmpz4 Ewel Il vs freq Repe5 custom pa Im 45 Ohm w O Same selection for all files Frequencies Hide Additional ariables st 7 ack keep previous axes process keep previous zoom Cancel Techniques and Applications Manual
165. ms Edit Remove Fig 163 Custom Units window to define new variables To create a new variable with its unit click on Add and put the name and the unit of the new variable in the frame Then click on d to validate The new variable is displayed in the list in blue color as a custom variable and can now be selected as the recorded variable for the analog inputs 6 Finally click on Configure to configure the selected channel to record the auxiliary input signal The new selected variables for Analog In1 and for Analog In2 are automatically displayed on the Cell characteristics window and activated for recording In the Selector the created variables are displayed and can be plotted These auxiliary variables can be used in several techniques as conditional limits of an experiment Note The parameters set in Analog Ini and Analog In2 to define the linear slope can be inverted to have an opposite variation of the recorded value with the plotted value SOCV Special Open Circuit Voltage As the OCV period the Special Open Circuit Voltage OCV consists of a period during which no potential or current is applied to the working electrode The cell is disconnected from the power amplifier On the cell the potential measurement is available So the evolution of the rest potential can be recorded This period is commonly used as preconditioning time or for equilibration of the electrochemical cell As for OCV diff
166. n 15 Techniques and Applications Manual brackets the potential step height and the duration are displayed according to the potential resolution defined on the top of the window in the Advanced tool bar From Ei V vs Ref Eoc Ei fixes the intial potential value in absolute Vs Ref or according to the previous open circuit potential E or according to the potential of the previous experiment E to E V vs Ref Eoc Ei fixes the limit potential value in absolute Vs Ref or according to the previous open circuit potential Eoc or according to the potential of the previous experiment E Hold E fort h mn S and record every dt S offers the ability to hold the first vertex potential for a given time and record data points during this holding period Record lt l gt over the last of the step duration selects the end part of the potential step from 1 to 100 for the current average lt I gt calculation to possibly exclude the first points where the current may be disturbed by the step establishment Note that the current average lt I gt is recorded at the end of the potential step into the data file averaged over N voltage step s averages N current values on N potential steps in order to reduce the data file size and smooth the trace The potential step between two recording points is indicated between brackets Once selected an estimation of t
167. n E 122 aek jJOCSEIOUON eaei avaneiaaatehortscvantaaatehardsovaneimaatehartiereemantws 123 SAP PITOCESS aa ee ee 124 3 2 2 Constant load GISCH AGS xix secnsec tattsacs tonnsec tach sacu corn aacudenn sacs tema aacu teen sacu lewd nanseeh ania 124 32 3 GPW COMStant POWER cerris paria pe p E oajaceva sejabendanieetes EE 126 324 GONSTaNT VONAGE CSV wticerteveiiereciites wetdareinedleeciiedey timed iveciieteey titel veateeteeedant 127 Techniques and Applications Manual ee 32 9 CONSTANT Current CSTO arana a sashersthecnlated a 129 3 3 SOMOS O02 sannin a a aa 131 See EVT Esr Vvorsus TIME kerra R Ea AE T A ER ET 131 3 3 2 LPs Linear PolarizallONksensensn a a 132 222l DESPUON esere aa r a E E 132 3 3 22 PROCESS ANG tits related to LP kccsteconteiinnna k 133 3 3 3 CM Corrosimetry Rp vs TiMe ccccccssececceseeeceeseeeceseesseeeessaseeeseeeesseneeeseaes 133 ISo WCSCHOLON enr O A 134 3 3 3 2 Applications of the Corrosimetry application ccccccceseeeecseeeseeeeeeeeeesaaees 136 3 3 4 VASP Variable Amplitude Sinusoidal microPolarization cccccccseeeeeeeeseeeeees 137 3 3 5 CASP Constant Amplitude Sinusoidal microPolarization c ccccccseeeeeeeeeeeees 138 336 GG Generalized COLOSION esis p E E S T A 139 9 9 0 DESCHOUOM bieo ae A E a a AN 141 3 3 6 2 Process and fits related to GC cccccccseccceeecseeeceeeeceeecesecseeseeeeseueesseesaueess 142 3 3 7 CPP Cyclic Potentiodynamic Pol
168. n T Open Circuit Potential and apply initial temperature No Open Circuit Potential and increase temperature Fig 137 General diagram of the CPT technique intial oe or oe 154 set Tj Rest for tg Techniques and Applications Manual 20 0 IE i h 0 rer Limit lt IdT dth gt lt dTg Z dtg with dig and dtg Record every dipg dERg ding 2 Scan Ewe with dE dt from Ej Hold E forty Limit ll gt Ty fort tg and I but no longer thant 1 00 E h ho ma 0 50 L 00 rn O om ono 0 166 ris 0 100 ova Eoc o hio mh e100 a 1000 8s pass mA is reached pass after I lt Record lt l gt over the last 25 ofthe step duration average H 5 voltage steps 500 p ERange 2 2 ean Tad Range 100 pA Bandwidth 100 p 4 602 4 mes 4 Jif pitting Il gt It Jor Te Creached goto 6 IE E 5 Increase T with Tg 10 0 below TL pass and T2 C above pass F h ho mn Limit lt ldT dtl gt lt dT4 Z dt with dTq4 1 00 ce D h ho mn ioo E oo mV Oo mm foomo goto 2 Rest for H and dty Record every dIpy dE R dtpy Stop controlling T SetTg joo E Fig 138 Detailed diagram of the CPT technique 155 Techniques and Applications Manual The whole sequence can be described with the following figure MEASURED E se
169. n limits Note the AQ value tested here versus AQy is the current sequence N integral charge And Analog In 1 Analog In2 lt gt L Vfort S sets limits of the sequence considering the value recorded with the analog input If the value reached L during t then the sequence is stopped and the next sequence is applied 3 5 3 Special Modular Galvano The Special Modular Galvano technique is very close to the Modular Galvano technique This technique allows the user to perform combination of OCV galvanostatic and galvanodynamic periods It is possible to chain these periods in any orders and to perform loops It gives a lot of flexibility to create galvano techniques The galvanodymamic mode can be used to study stepwise electron transfer reactions and multicomponent systems In the Special technique a limit condition on analog input is set e Mode selection Click on Mode OCV 0 Potentiostatic 1 or Potentiodynamic 2 to select the corresponding mode Then the detailed diagram is automatically displayed e Open Circuit Voltage Mode 0 the open circuit voltage is the standard block So report to the OCV technique section 2 1 1 page 5 for more details e Loop goto Ns for nc time s each one of the OCV potentiostatic and potentiodynamic periods is represented by a single line into the grid parameters If n is set to 0 the sequence lines are executed one after one Then an OCV potentiodynamic and OCV seq
170. nce line number 2 4 2 2 Potentiostatic Mode 1 o Oc 0 Mode Potentiostatic 1 Fotentiodynamic 2 SetEweto Es p000 i ys Ref 7 forts o hf mn foomo Limits Imax pass imi Imin pass imi AGI gt AG 0 000 mah gt Record cb every dts 01000 ERange 2 2 ena Aad Range Auto 7 Bandwidth 7 Go back to sequence Ne p JORGE arate Te ae for mg E imela EPAM a A Ns afi 2 Fig 61 Modular Potentio potentiostatic detailed diagram Set Ewe to Es V vs Ref Eoc Ectrl Emeas sets the potential to a FIXED value vs Ref the reference electrode potential or RELATIVELY to the previous open circuit potential E or to the previous controlled Eet or measured Emeas potential in linked experiments or linked sequences for t LETE MN 5 S defines the potential step duration if not stopped on limits Limit to Imax PA A and to Imin pA A And AQ to AQny fA h A h pC KC sets limits for the potential step If one limit is reached I gt Imax or lt Imin AQ gt AQy before the end of the step duration ts then the program proceeds to the next sequence A zero value disables the AQy limit and typing p to enter pass disables the Imax and Imin limits Note the AQ value tested here versus AQy is the current sequence N integral charge Record I every dl pA A dQ
171. ncies the delay may be long Average Na measure s per frequency repeats Na measure s and average values for each frequency Drift Correction corrects the drift of the system This feature is more specially dedicated to low frequencies enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment Range Bandwidth sets the current range and the bandwidth for the whole experiment 3 3 5 CASP Constant Amplitude Sinusoidal microPolarization Constant Amplitude Sinusoidal microPolarization is used to determine the corrosion current and the corrosion coefficients of a tafelian system A sinusoidal voltage is applied around the corrosion potential Ecorr with a small amplitude Va and a constant low frequency fs This technique is associated to a dedicated fir CASP Fit this analysis tool uses a direct Fourier transform and the amplitude of the harmonics are determined and used to calculate the corrosion parameters This technique is faster than ther standard polarization technique and there is no need to know the corrosion coefficient values This technique is available on channel board with and without EIS ability Ewe TFA Wa E corr Time frequency T ne cycles Fig 124 Principle of the Constant Amplitude Sinusoidal microPolarization technique and its associated analysis
172. nd at the end of the pulse I lbp E step V step potential value resulting from the potential sweep and used to plot the current 63 Techniques and Applications Manual 2 4 Technique Builder Insert Techniques gt Electrochemical Techniques fob ee Yoltamperometic Techniques hom Impedance Spectroscopy fe Pulsed Techniques 3 a et Technique Builder Modular Potentio MP Modular Galvano MG z f L Trigger In TI z L Trigger Out TO ASO Wait i Temperature Control TE le Rotating Disk Electrode Control ADEC External Device Control EDC fee Ohmic Drop Determination gt Electrochemical Applications Insert Technique Load from default Custom Applications Before Advanced setting _ External devices F After W Cell characteristics Rename Add Remove Fig 53 Technique builder selection window This section is dedicated to experiment building With the techniques and tools described in this section the user has the ability to easily create his own application with linked techniques and eventually to save the created experiment in the custom applications The Modular Galvano and Modular Potentio techniques have been designed to cover all the electrochemical fields and experiments thanks top a modular approach Linked with Triggers Wait periods external device control methods and loops these techniques become powerful enough to build complex settings 2 4 1 MG Modular Galvano
173. nd step potential sweep with threshold pitting detection sequence Scan E with dE dt mV mn fixes the scan rate dE dt in mV mn The software adjusts the potential step amplitude and its duration 163 Techniques and Applications Manual From Ei V vs Ref Eoc Ectrl Emeas to Ep V vs Ref Eoc Ei from a potential E defined in absolute vs Ref the reference electrode potential or versus a previous open circuit potential Eoc previous controlled potential Een or previous measured potential Emeas to Ep value defined in absolute or versus Eg or Ei Record e lt I gt over the last of the step duration averaged N voltage steps el every dl HA or dt S Two different recording conditions on the current are available with the potentiodynamic mode either recording an averaged current lt l gt on each potential step or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ Until I gt lp pA A after t S fixes the threshold pitting current Ip to detect Setting of a blanking time t eliminates a possible large peak of current when just applying the initial potential step in case of large AE value enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adju
174. ne calculation defined in EC Lab software the crest factor values are included between 2 and 3 u t Um Um Fig 20 Scheme of multisine signal To avoid a large excitation at the sine origin that could damage the electrochemical cell all the sine are out of phase the ones compared to the others Indeed in multisine measurement a multiplicative factor can be applied on the signal amplitude which can reach Um or Um values Generally it is better to not exceed 50 mV of sinus amplitude Indeed if the excitation which is the sum of the maximum amplitude of all the applied frequencies is too large this might result in a measurement in the non linear response domain of the electrochemical cell Then the sine amplitude values need to be minimized and accordingly the non linear response of the system is minimized Obviously the number of frequencies summed depends on the user needs defined in the settings of the electrochemical impedance spectroscopy technique In EC Lab software multisine measurement is done simultaneously on a maximum of two decades If the experiment is defined with more than two decades of twenty sine the cutting out is automatically done by set of twenty sine To avoid noisier or non linear results user has to define carefully the experimental conditions An appropriate level of excitation has to be defined Indeed since a lot of frequencies are stimulated in the same time there is less signal
175. ne the semi conductor parameters flatoand potential donor density For more details about this plot refer to the EC Lab software manual Note lt is possible to modify the settings of an impedance measurement during the experiment The user can Modify Pause Resume or Stop the experiment it s while running 2 2 5 2 2 Application The SPEIS technique is applied in this example to circuit 3 of Test Box 3 A potential sweep is made from E 0 V to E 2 1 V with 100 mV potential steps On each step an impedance measurement is performed for a whole frequency range 200 kHz to 1 Hz 48 Techniques and Applications Manual Channel 1 Graph Sel al ve Ewe staircase potElS 01 CA impr 8 le vs Ewe staircase potElS 03 CA impr th D na a l 2 000 Re Z Ohm Fig 38 Application of the SPEIS technique The user can plot 1 C vs Ewe of this data file either for few frequencies or the whole frequency range 49 Techniques and Applications Manual 2 3 Pulses 2 3 1 DPV Differential Pulse Voltammetry DPV is very useful for analytical determination for example metal ion quantification in a sample The differential measurements discriminate a faradic current from a capacitive one In this technique the applied waveform is the sum of a pulse train and a staircase from the initial potential E to a limit potential Ey or to the final potential E if the scan is reversed The current is sampled just
176. nnnnnnnnnenrnnnrrenersnrrnnenenenne 65 24 12 Galvanostatic MOde 1 anea a a 66 241 3 Galvanodynamic Mode 2 Jaranan E EE 67 2 4 1 4 Sequences with the Modular galvano teChnique ccccseeeceeeeseeeeeeeeseeeeaes 68 242 MPS Modular Potent O erra wads saan seessassealebasnsdeatins ate A 68 2 4 2 1 Open Circuit Voltage Mode 0 0 0 ceeccccecccceeeeeseeeeteeceeseeeeseeeesseeeeseeeesaeeeeas 69 24 22 Poteniostatic Mode T 2 2 nctsuacercuiacesdcnsdehiyn cack eatetavinalietelivatueieiae 70 2 4 2 3 Potentiodynamic Mode 2 iis 6 0Siecteactereta dite didaclvedstacdoetaedodacloetnceceadie 71 Techniques and Applications Manual eo UMC Ue od otantets aia a ie ota a bie T bie ota pcncetae bie a bie ota eiamcetaa hie ense 72 244 Tine Wait ODOM areira ipeni nEs narii TEE PECES PATEE PERCEN DENTARE PERE ATLE i 74 245 Temperature GOntrol TG sesciecsaseneteins dcaece n 74 2 4 6 Rotating Disk Electrode Control RDEC oe eeccccccceceeeeeeeeeeseeeesaeeeesaeeesaeeeees 75 ea Extemal Device Contool ED C vias nti cdigrccinedt eersmathrnuanss iewueety iden soraentaiatneeatiens 77 24 0 IME LOOD ODION saion ane tseceawali th anstadyerencisthanaednaeancedev cestsdvagennadeshanccens 77 2 4 9 The Pause technique 1 1c cscctiesdstirescsuatenedsetindsGsechexsdseturantsusiaardsetieaed aecteuiaeteeeadauateane 78 2 5 Manual Conto kasenin A E een tecntuanweeawnenis 79 Zo PolenialManuakoon Olsona 79 252 Ginen Manua l OOTO a aaah c
177. nrnnrrrrnrrnrrnrrnrrarrnrrnrrnrrnernereene 171 3 4 3 SPFC Stepwise Potential Fast Chronoamperometry cccseccceeeeseeeseeeeseeeeaes 175 3 4 4 PEISW Potentio Electrochemical Impedance Spectroscopy Wait c cce 177 3 4 5 How to add a homemade experiment to the custom applications c0ee 178 3 5 opec AODIICATONS woes has tees and Grantee haan alontiels fot na Wiaeieo l fae cal ati au none 179 3 5 1 SOCV Special Open Circuit Voltage srera pena apee p REEE ERGE 181 3 5 2 SMP Special Modular POtentiO cccccccceecceseecseeecececeueeceeeceucesueeeeeessueesseesaas 182 35 39 Special Modular GalVan xccseeheteddved inai EEE eesti 187 3 5 4 SGCPL Special Galvanostatic Cycling with Potential Limitation 008 190 Linked Experiments risse a E SA EE EREE 194 4 1 DESCrIDUOM AMG SETING Ss neea eatin ab a dadca eating Mb sagatoenseneiaaen 194 4 2 Example of linked experiment ccccsecccceeeeceececeeeeeceeeeseueeeeeeeensueeeseeenesensneeens 195 4 3 ADICA TON an sccacachacshetan ane taacy sc hncianedccun stad ntanlatedanae teh aaaanahacuuctetsanienatacenatadaruiacetennues 196 Stack experiments aessscsecas see cctancewic eNA MaI r ana aA EIKE AANEEN 199 Summary of the available techniques and applications in EC Lab cce 204 List of abbreviations used in EC Lab Software s csssesssessssseesssesssessseesseeeeseens 206 GIOS Salyne Ea eNi 208 Iae D E E E E EEE E E AE AE E
178. nstant Voltage Catv Larl Constant Current Cstl ig Corrosion gt fe Custom Applications gt e Special Applications Insert Technique Load from default Custom Applications Before Wl Advanced setting _ External devices After Cell characteristics Rename Add Remove Stack Cancel Fig 112 Photovoltaic fuel cell applications 3 2 1 l V Characterization IVC l V characterization is intensively used to carry out investigations on Photovoltaic or Fuel cells The principle of this technique is to apply a linear potential sweep and to measure the corresponding current and power Some characteristic parameters of the cell such as maximum current maximum potential and maximum power can be determined 122 3 2 1 1 Techniques and Applications Manual Description Rest fort p o hi m soos Limit IdE wedtl lt dEp dt 00 meh Record every dEp oO m odtR 01000 3 acan Ewe with dE dt 01 EE rent ys from Ej to EL Record ib over the last 25 Z of the step duration average H 5 voltage steps ERange 2 2 exci Fae Range Auto Bandwidth 7 de dt 100 py 602 4 me JEN 500 pi Fig 113 Detailed diagram of the l V Characterization e First step rest potential or open circuit sequence Rest for tp ee MN nannan S fixes a defined time duration tp for recording the rest potential or until dE dt lt dEp dt mV h gives the user the
179. nt limit has not been reached during the previous phase I lt lp then the final potential of the scan E is held until the current reaches the I limit If the current limit has been reached during the previous phase I gt lp then this block is skipped even if checked e Fourth step reverse scan Reverse scan towards E V vs Ref Eoc Ei if checked then apply a potential scan from the current potential to E that can be set to a fixed value vs Ref the reference electrode potential or relatively to the previous potential E Or Ege or until I lt pA A defines a current limit for the reverse scan If I lt l then the scan is stopped before the EL potential is reached A zero value disables the test At the end the working electrode is disconnected 145 Techniques and Applications Manual 3 3 8 Dep Pot Depassivation Potential The Depassivation potential is the concatenation of the MPSP without the I test and MPP techniques see figure below First the MPSP technique is used to depassivate the electrode metal while applying the appropriate potential The MPSP technique can be considered as a pre conditioning step where the electrode surface is cleaned Secondly the MPP technique is used to study the corrosion pitting Begin End Fig 130 General diagram of the Depassivation Potential application 146 Techniques and Applications Manual a cil 7 ee Z wr c
180. nt range and bandwidth values for the entire experiment Note It is highly recommended to not use the automatic current range with pulsed techniques The resolution of each range is different and dynamic current range changes may lead to have spikes on the plot RNPV recorded and calculated variables The variables below are stored into the RNPV raw files mpr State byte time s control V g Ewe V lt l gt mA Q Q mA h And the next variables are calculated from lt l gt or from the potential to save size on disk forward mA lt l gt values at the end of the pulses lp reverse mA lt I gt values before the pulses lbp delta pA difference between lt l gt values before and at the end of the pulse lp lbp E step V step potential value resulting from the potential sweep and used to plot the Current 2 3 6 DPA Differential Pulse Amperometry The Differential Pulse Amperometry results from the DNPV technique without increasing pulse steps The potential waveform and the current sampling are the same as for DNPV A DPA experiment is often used as a sensitive method for the quantification of electrochemical species at a defined potential E This potential value is often determined with a DNPV experiment using a potential sweep with the same waveform previously performed This technique is dedicated to the quantification of biological electroactive species 61 Techniques and Applica
181. ntial scan speed One can enter dE dt the software will automatically calculate the corresponding staircase values dE and dt that minimise the potential steps dE However it is possible to directly set the dE and dt values from E V vs Ref Eoc Ectrl Emeas defines the initial potential E to a FIXED value vs Ref the reference electrode potential or RELATIVELY to the previous sequence final open circuit potential Esc or controlled potential Ect or Measured potential E meas to E V vs Ref Eoc E defines the final potential E in absolute vs Ref the reference electrode potential or relatively to the open circuit potential Esc or to the initial potential Ei Limit to Imax PA A and to Imin PA A And AQ to AQy fA h A h pC kC sets limits for the potential step If one limit is reached I gt Imax or lt Imin AQ gt AQm before the end of the step duration ts then the program proceeds to the next sequence A zero value disables the AQy limit and typing p to enter pass disables the Imax and Imin limits Note the AQ value tested here versus AQy is the current sequence N integral charge Record lt I gt over the last of the step duration averaged N voltage steps every dl HA or dt S two different recording conditions on the current are available with the potentiodynamic mode either recording an averaged current
182. ntification A frequency Domain approach Ed IEEE Press 2001 Van der Ouderaa E Schoukens J Renneboog J IEEE Trans Instrum Meas 37 1 1988 145 147 Schoeder M R Pintelon R Rolain Y IEEE Trans Instrum Meas IM 49 2000 275 2 2 2 PEIS Potentiostatic Impedance 2 2 2 1 Description The PEIS experiment performs impedance measurements into potentiostatic mode by applying a sinus around a potential E that can be set to a fixed value or relatively to the cell equilibrium potential Begin Apply a constant potential E And perform impedance measurements from frequency F to F Fig 21 PEIS general diagram The potential of the working electrode follows the equation E E V sm raft we a The detailed flow diagram is made of four blocks that can be separated into four parts single or multi sine mode initial potential frequency scan with recording conditions repeat sequence 32 Techniques and Applications Manual ats za 00 000 00 000 kHz E All mHz ii Show frequencies gt gt oo om a bo EL Go back ta seq Ne fr JORG aaa feces for my D tirnels JE AV ARE SAA a increment cycle number lt E Fig 22 PEIS detailed diagram e Initial potential Set E to E V vs Ref Eoc Ectrl Emeas for te D eee mn S sets the potential to a fixed value E vs Ref the reference electrode potential or relatively to the previous
183. ntiostat switches from an open circuit voltage mode to a galvanostatic mode or the vice versa Bandwidth represents the frequency of the regulation loop of the potentiostat It depends on the electrochemical cell impedance The bandwidth values go from 1 to 7 with increasing frequency Calibration operation that must be done for each channel in order to reduce the difference between a controlled value for example Eet and the corresponding measured value for example Ewe Channels each one of the boards corresponding to an independent Potentiostat galvanostat Chronoamperometry chronocoulometry controlled potential technique that consists of stepping the potential of the working electrode from an open circuit potential to another potential E where electrochemical reactions occur The resulting curve is a current time response Chronocoulometry is an alternative mode for recording the charged passed as a function of time with current integration Chronopotentiometry controlled current technique where the potential is the variable determined as a function of time during a current step Compact mathematical function allowing the user to compress data points from the raw data file Compact functions are available with GCPL and PCGA techniques All points of each potential step are replaced by their average taken at the end of the potential step The number of points of the compacted data file decreases a lot according to the raw file C
184. o 4 all 0 500 25 a i 4 4 dE dt 100 pY 600 0 ms JEM 100 py Fig 131 Detailed diagram of the Depassivation Potential application e First step rest potential or open circuit sequence Rest for tp h nanana mn a S fixes a defined time duration tp for recording the rest potential or until dE dt lt dEp dt mV h gives the user the ability to shorten the open circuit period at the time when the decay of the potential is lower than a given value 147 Techniques and Applications Manual Record Ewe with dEp mV resolution and at least every dtr S allows the user to record the working electrode potential whenever the change in the potential is gt dEr or every dtp time interval Data recording with dEr resolution reduces the number of experimental points without loosing any interesting changes in potential When there is no potential change only points according to the dtg value are recorded but if there is a sharp peak in potential the rate of the potential recording is governed by the potential recording resolution e Second step potentiostatic period with pitting limit for the current Set Ewe Es v vs Ref Eoc Ectrl Emeas for t Maar MN es S sets the potential directly vs Ref the reference electrode potential or with respect to the final rest potential value Eoc or previous controlled potential Eer or previous measur
185. olumns are time s differential or absolute and current A Apply Es 3500 Y for ts m hi E mr 3 2000 Record even dis o 0 m dts 0 1 OU o ERange oV 5 uss Greaney Fea i Range Gobackto seq Ns 0 RGSS aagk facia for nge m limes ETAN EET wage Ne 4 0 2 3 4 5678 9 1D Fig 108 PPI detailed diagram Automatically the number of Sequences corresponding to the number of rows in the table is displayed The maximum number of sequences is limited to 2500 on our standard boards limited by the memory size in the case that the software fnid two lines with teh same parameters they will be merged in only one line to save memory In the table to import the first column must the time and the second one must be the other variable such as potential or current e Pulsed potentio Charge Apply E V for t E mn sS define the voltage pulse value and duration Record every dl pA A and or dts S limits the recordings conditions in current variuation and or time variation enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range and Bandwidth fixes the current range and bandwidth for this experiment 118 Techniques and Applications Manual e Conditional test which proposes to go to the next sequence or
186. onditions the technique will do the following set of sequences 2 times 3 times 3 times 3 times Ns 0121212123 121212123 121212123 Thus after the initial sequence 0 there will be 4 cycles on steps 1 2 repeated 3 times 93 Techniques and Applications Manual Warning 1 When running a charge sequence I gt 0 the final value of the working electrode potential E_ must be set at a lower value than the first limit value Ey This is due to the fact that at the end of the current on period charge the working electrode potential reaches a maximum and decreases during the open circuit period which follows If E_ is set at a higher value than Ey the experiment will never reach the limiting condition test Ewe gt EL and the technique will always loop on the first step Similarly when running a discharge sequence I lt 0 the final value of the working electrode potential E must be set at a higher value than the first limit value Ey At the end of the discharge the working electrode potential reaches a minimum and increases during the rest potential period If E is set at a lower value than Ey the experiment will never reach the limiting condition test Ewe lt E and the technique will always loop on the first step Warning 2 When setting values in the diagram or the table s line the user must set variables to O if he requires this particular value Otherwise the program will detect an empty cell and will end the technique
187. onstant load discharge CLD technique especially designed for battery testing This technique is used to discharge a battery at a constant resistance The potentiostat is seen as a constant resistor by the battery Constant power CPW This technique is designed to study the discharge of a battery at constant power The control is made by checking the current to maintain an E l constant Corrosimetry application used in corrosion for the determination of R versus time by a repetition of the polarization around the corrosion potential at fixed time interval Cycle inside a technique this term is used to describe a sequence repeated with time 208 Techniques and Applications Manual Cycle number processing function that allows the user to display on the graphic one or several cycles chosen in the raw file The selected cycles are lightened and the others are hidden Cyclic potentiodynamic pitting CPP corrosion technique used to evaluate pitting susceptibility and made with a potentiodynamic part and a conditional potentiostatic part which is taken into account if the pitting current is not reached during the potentiodynamic part Cyclic voltammetry CV this technique consists of linearly scanning the potential of the working electrode and measuring the current resulting from oxydoreduction reactions Cyclic voltammetry provides information on redox processes electron transfer reactions and adsorption processes Depassivation p
188. operation faster when the limit potentials have not been properly estimated and continue the scan without damaging the cell Note it is highly recommended that the user adjusts the potential resolution from 300 uV for 20 V amplitude to 5 uV for 0 2 V amplitude with a SP 150 VSP or VMP3 according to the experiment potential limit This will considerably reduce the noise level and increase the plot quality 3 Hold E While the experiment is running clicking in this button allows the user to hold the actual potential Clicking again on this button the experiment will continue in the same direction 4 Table Sequence The CVA technique is equipped with a table the ability to add sequences This allows the user to link several sequences of CVA with different scan rates or different vertex potentials Graph tool Process Data When the CVA experiment is made the user can extract the charge quantities exchanged during the anodic step Q charge the cathodic step Q discharge and the total charge exchanged since the beginning of the experiment Q Q Techniques and Applications Manual 2 1 4 Linear Sweep Voltammetry LSV The linear sweep voltammetry technique is a standard electrochemical protocol Unlike the CV no backward scan is done only the forward scan is applied This technique is specially dedicated to RDE Rotating Disk Electrode or RRDE Rotating Ring Disk Electrode investigations which allows user to carry out steady sta
189. ory set 4 mA at 25 C 20 mA at 120 C If external thermostats are used the user needs to define the control calibration values temperature range corresponding to specific thermostat in use Quite often as with the Ministat and Eurotherm controllers the temperature range can also be changed in the thermostat itself Click on the Apply button to validate the settings Once this is done the Manual control slidebar allows manual setting and activation of the temperature of the cell This menu can be activated without any TCU unit but will only have effects for the VMP systems equipped with TCU unit Note if the temperature is activated for a channel all the experiments will record the temperature This will be then possible to run the OCV and see the effects of manual changes of the temperature This menu can be used in the same way to control rotating electrode speed instead of temperature In this case select Device Type RDE Then the Temperature Rotating speed configuration window will allow the user to set manually the rotating speed The Wait technique can be used to control the rotating speed in an experiment Once the thermostat has been configured the CPT experiment can be loaded for a given channel the same way as the other experiments the CPT technique is located into the Corrosion section of the EC Lab techniques The next figures show the CPT diagram 153 Techniques and Applications Manual Begi
190. ositive electrode of the cell is connected to the working electrode cable red Limit Ecel gt Ey F V fixes the limit of the working electrode potential under charge discharge see warning 1 Record E every dE mV and at least every dt Ss allows the user to record the working electrode potential with a given potential resolution whenever the change in the working electrode potential is gt dE or and at least every dt time interval 2 Potentiostatic period Hold Ey for ty Hwee mn s and limit I lt Im pAl A allows the user to stand at the potential Ey for a given time or until the current reaches a low limit value lp lf the limit potential Ey is not reached within the time t or if ty is set to 0 the system skips to the next step Record AQ every dQ mA h and at least every dt S in the constant potential mode the system acts as a coulometer and a recording is performed every time the charge increment decrement since the previous recording is gt dQ and or every dt time interval Limit AQ to AQy mA h lt gt AXy fixes the maximum charge change from the beginning of this sequence during the sequence This charge is equivalent to a Axy quantity which corresponds to a normalized charge related to intercalation electrodes enables the user to select the potential range for adjusting the potential resolution with his system See EC La
191. otential DP corrosion technique composed with a potentiostatic part used to depassivate the electrode metal and with a potentiodynamic part used to study the corrosion pitting Differential Pulse Voltammetry DPV technique used in analytical electrochemistry to discriminate faradic from capacitive current This technique consists of pulses superimposed on a potential sweep Differential Normal Pulse Voltammetry DNPV technique used in analytical electrochemistry to discriminate faradic from capacitive current This technique is made of increasing prepulses with time and pulses superimposed on the prepulses Differential pulse amperometry DPA technique used in analytical electrochemistry to discriminate faradic from capacitive current This technique consists of the repetition of a pulse sequences made with a prepulse and a pulse superimposed EC Lab software that drives the multichannel potentiostats galvanostat Galvanostatic cycling with potential limitation GCPL battery testing technique corresponding to battery cycling under galvanostatic mode with potential limitations and with the ability to hold a potentiostatic mode after the galvanostatic one Galvanostatic cycling with potential limitation 2 GCPL2 battery testing technique similar to the GCPL but with two potential limitations on the working electrode and on the counter electrode potential The potential is not held after the current charge discharge Galvanostatic cycl
192. otential resolution adjustment range bandwidth enables the user to select the current range and the bandwidth damping factor of the potentiostat regulation e Loop goto Ns for nc time s allows the experiment to loop to a previous line Ns lt N for n times The number of loops starts while the loop block is reached For example on N 3 if one enters goto Ns 2 for nN 1 time the sequence N 2 N 3 will be executed 2 times nN 0 disables the loop and the execution continue to the next line Ns Ns 1 If there is no next line the execution stops Report to the battery techniques section 3 1 page 83 for more details on loop conditions Here it is possible to loop to the first instruction N 0 and the current instruction Ns Ns This is different from battery experiments GCPL and PCGA where the first instruction has a special meaning and there is still a loop on the current instruction This technique uses a sequence table Sequences of the Chronoamperometry Chronocoulometry technique can be chained using the Table frame The first sequence is N 0 Each line of the table N corresponds to a rest and potential step sequence The sequences lines are executed one after the other and it is possible to loop to a previous sequence line Ns Example Setting E Eo AEio on the first sequence N 0 and Ej Epe AE on the next sequence N 1 with a loop on the sam
193. otential step or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment Range and Bandwidth Defines the current range and the bandwidth for the whole experiment Range is automatically set according to and values Contrary to the MPP technique no current limitation is available with the linear polarization application 3 3 2 2 Process and fits related to LP The LP application can be used for Rp and kor determination using the R fit see EC Lab software manual for more details It can also be used to determine the corrosion rate with the Tafel fit see EC Lab software manual for more details 3 3 3 CM Corrosimetry Rp vs Time This application is advanced in corrosion tests It is designed to follow the corrosion standard values Rp Ecorr lcorr evolution versus time for very a long time several months It consists of periodic linear potential sweeps around the corrosion potential Egor The current is 133 Techniques and Applications Manual measured during the potential scan According to the recording conditions on the current either one point is plotted as an average on each potential step or several points are plott
194. ow for a profile importation Select the PPI application and click on OK The following window is displayed Import Settings From Text File OO di Developpe profil test batterie urbain v Organiser Nouveau dossier Fr Favoris Z Nom Modifi le ME Bureau __ application courant 20 10 2009 17 00 Emplacements r urbain_Sminutes 03 09 2009 10 44 p T l chargement Bibliotheques Documents Images al Musique E Vid os jE Ordinateur Disque local C ca donnees Ds Ge sys 192 109 20 4 Nom du fichier Text files TAT Fig 107 Text Import window 117 Techniques and Applications Manual The user has to select the text file to import with two columns time and potential in this case This technique corresponds to battery cycling under galvanostatic mode This technique is specially designed to fit with the urban driving patterns designed to test EV batteries The particularity of this technique is the large number of sequences available and the fact that the experimental settings can be defined by importation of a text file This technique can be used in charge and in discharge mode depending on the sign of the current Note that experimental limits are not present in the setting it is highly recommended to use safety limits located in the Advanced Setting window to avoid overcharge or overdischarge of the batteries The text file importation c
195. p Record even dq 5 0 nn 60 0000 2 ho ma jooood 5o00 ma or dtg Limit A O gt ADW g X Ww E Range Range Bandwidth Rest for tp Limit IdEwe dt lt dEp dt Record ever dep or dtp 1 000 mah 30 0000 3 0000 im4h 0 000 Ov oY Arena Ale 100 m 4 1 ho m pon Bo mvh oo my 1o 0000 s ED Oa fade Agia go A Ayi 3 e a DR cele Gp 4 Go backto seq Net f PORTS ante eas for mg 5 time s Aviva SARAN Me o 1 2 Fig 92 Detailed diagram of one GCPL 5 sequence 101 Techniques and Applications Manual 3 1 6 1 Description of a galvanostatic sequence Fig 92 e first step galvanostatic period that can be followed by a potentiostatic period 1 Galvanostatic period Set I to ls pA A vs lt None gt Ictrl Imeas for at most t LETTS mn fixes the current value in absolute or versus the previous controlled current or previous measured current the sign for reduction and for oxidation and the maximum duration of the imposed current period enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment lrange and Bandwidth defines the current range and bandwidth for this experiment Record Ewe up to tmax s with geometric progression of t
196. p Rest Executes a rest potential period similar to the initial one At the end the working electrode is disconnected 3 3 6 2 Process and fits related to GC Like the LP the GC application can be used for Rp and leor determination using the R Fit see the EC Lab software manual for more details It can also be used to determine the corrosion rate with the Tafel Fit see the EC Lab software manual for more details 142 Techniques and Applications Manual 3 3 CPP Cyclic Potentiodynamic Polarization The Cyclic Potentiodynamic Polarization is often used to evaluate pitting susceptibility It is the most common electrochemical test for localized corrosion resistance The potential is swept in a single cycle or slightly less than one cycle The size of the hysteresis is examined along with the difference between the values of the starting open circuit corrosion potential and the return passivation potential The existence of hysteresis is usually indicative of pitting while the size of the loop is often related to the amount of pitting This application is based both on the MPP and MPSP techniques except that the potentiodynamic phase is done before the potentiostatic one some phases are optional and there is an additional potentiodynamic phase Begin End WE Fig 128 CPP general diagram The detailed diagram is made of five blocks Initial Rest Potential Sequence Potential sweep with threshold pitting detect
197. possible large peak of current when just applying the initial potential step in case of large AE value The cell is disconnected at the end of the experiment 3 3 9 CPT Critical Pitting Temperature Available instruments with the CPT application VMP3 BiStat VS HCP EPP SP CLB Instrument MPG VMP VMP2 Z Z Z P 803 400 4000 150 500 4 20 mA x 10 10 V x x x x x x x The CPT technique can be performed by most of our instruments The levels of automation in this technique are different according to the selected instrument Historically designed for the VMP the CPT technique was fully automated with a TCU Temperature Control Unit and any thermostatic bath controlled by a 4 20 mA analog input Huber Ministat Eurotherm 2408 This technique can be used with or without VMP boosters It has been written Originally to allow the VMP to perform the standard and extended ASTM G150 methods It has been extended to the other instruments of our product range that are provided with 10 to 10 V analog inputs output instead of the 4 20 mA of the VMP 3 3 9 1 Differences in the CPT technique between the VMP and the other instruments The following describes the main differences between the VMP and the other instruments of Our range Features CMP Other _ Multi corrosion cell Master channel for temperature control Yes N0 Analog input Current 4 20 mA Potential 10 10 V Temporization synchronization a E a To u
198. potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment range bandwidth enables the user to select the current range and the bandwidth damping factor of the potentiostat regulation Reverse scan towards E offers the possibility to do a reverse scan towards E 2 2 Electrochemical Impedance Spectroscopy Methods employing excitation of an electrochemical cell by a sinusoidal signal were first employed as a way of measuring the rate constant of fast electron transfer reactions at short times Now the interest rests on the complete analysis of what are often complicated processes involving surface and solution reactions electrode and electrolyte Among the modern computational techniques the Electrochemical Impedance spectroscopy EIS is now a powertul tool for examining many chemical and physical processes in solution as well as in solids EIS has uses in corrosion battery fuel cell development sensors and physical electrochemistry and can provide information on reaction parameters corrosion rates electrode surfaces porosity coating mass transport and interfacial capacitance measurements The VMP2 Z VMP3 VSP SP 150 boards are designed to perform impedance measurements independently or simultaneously from 10 WHz to 1 MHz 200 kHz for channel boards delivered before July 2005 For SP 300 and SP 200 the maximum frequency is 7 MHz Since the
199. ps being replaced by current steps The constant current is applied between the working and the counter electrode This technique can be used for different kinds of analysis or to investigate electrode kinetics But it is considered less sensitive than voltammetric techniques for analytical uses Generally the curves Ewe f t contain plateaus that correspond to the redox potential of the electroactive species 20 Techniques and Applications Manual End yO to Ns or Ne End ao 8 aA td Se om oO To oS a 1 Som oF Fig 12 Chronopotentiometry general diagram This technique uses a sequence table also Each line of the table N corresponds to a rest and current step sequence The detailed diagram is made of two blocks e current step e loop 21 Techniques and Applications Manual Soo pA s lt None gt h lo mm oo000 pass Y AOI gt AQpa ii 49 889 rd Fi Record pamm ever dE odts 01000 Range 100 p Bandwidth Go back to sequence Ns p oa ee Aaa for Mp E timels EAYN aaa Fig 13 Chronopotentiometry detailed diagram e Current step Apply I pA A vs lt none gt Ictrl Imeas the current step is set to a fixed value or relatively to the previous controlled current le that is the current of the previous sequence current step block or to the previous measured current Imeas This option is not ava
200. quences selection 1000 0 1001 0000 e r 2000 0 0 00 1 0000 01701720 00 00 00 3000 0 0 00 1 0000 01701720 00 00 00 4000 0 0 00 1 0000 01701720 00 00 00 S000 0 00 17 O000 01701720 00 00 00 Fig 69 Wait table Caution The RDEC technique has a parameters table in the parameters settings window which can be related to the sequences selection The user can link several RDEC sequences Ns 0 to n These sequences are linked differently from the other techniques In other standard technique one sequence is executed directly after the other For the RDEC technique each sequence corresponds to a loop of a linked technique see after Therefore only one sequence of the wait technique is executed at each loop of the linked experiment The sequences are considered successively at each loop This allows the user to increase temperature values at each sequence loop lf more experiment loops than the number of sequences are set in the RDEC experiment table then the RDEC technique is restarted from the beginning 76 Techniques and Applications Manual 2 4 7 External Device Control EDC The External Device Control EDC technique allows the user to control an external device and change external device parameters during the experiment A direct link to the External Device window is done by clicking on the underlined words The EDC technique contains a table then the user can link several EDC sequences row Ns 0 to n Only one row of t
201. r hi hao mn 55 V Record ever dE 0 00 mi di foo a 0 1 Fig 66 Wait Wait with previous control For ty h Mn s O from technique begin It is possible to choose the wait duration ty In that case the duration can start at the end of the previous technique or the beginning of a particular technique Until the month day year h mn The user can define the date of the end of the wait technique until Record every dE mV dl pA A and dt s choose one or several recording conditions 2 4 5 Temperature Control TC The Temperature Control TC technique allows the user to control a temperature and change it during the experiment A direct link to the External Device window is done by clicking on the underlined words The TC technique contains a table then the user can link several TC sequences row Ns 0 to n Only one row of the table is executed at each loop of the experiment beginning to Ns 0 and is incremented with the following loops This tool allows the user to have for example an increase of the temperature values and to maintain during a defined duration this temperature value before each step 74 Techniques and Applications Manual Set temperature to oo Coon External Thermostat and wait with previous control for tg o h oo mr 0 0000 z Record ever dE 0 00 ivy di 0000 mA dt O00000 s 25V 25V
202. r a given time and record data points during this holding period 12 Techniques and Applications Manual Note This function can correspond to a preconditioning capability in an anodic stripping voltammetry experiment e First potential sweep with measurement and data recording conditions Scan Ewe with dE dt mV s allows the user to set the scan rate in mV s The potential step height and its duration are optimized by the software in order to be as close as possible to an analogic scan Between brackets the potential step height and the duration are displayed according to the potential resolution defined on the top of the window in the Advanced tool bar to vertex potential E V vs Ref Eoc Ei fixes the first vertex potential value in absolute Vs Ref or according to the previous open circuit potential Eoc or according to the potential of the previous experiment E Hold E fort h mn S and record every dt S offers the ability to hold the first vertex potential for a given time and record data points during this holding period Measure lt l gt over the last of the step duration selects the end part of the potential step from 1 to 100 for the current average lt I gt calculation to possibly exclude the first points where the current may be disturbed by the step establishment Note that the current average lt I gt is recorded at the end of the potential step in
203. r data storage on line visualization and off line data analysis and display This architecture ensures a very safe operation since a shut down of the monitoring PC does not affect the experiments in progress The application software package provides useful techniques separated into two categories Electrochemical Techniques and Electrochemical Applications The techniques contain general voltamperometric Cyclic Voltammetry Chronopotentiometry differential techniques impedance techniques and a technique builder including modular potentio and galvano triggers wait and loop options The applications are made of techniques more dedicated to specific fields of electrochemistry such as battery fuel cells super capacitors testing corrosion study and custom applications Electrochemical techniques and applications are obtained by associations of elementary sequences blocks and appear as flow diagrams combining these sequences The settings can also be displayed as column setup Conditional tests can be performed at various levels of any sequence on either the working electrode potential current or on the counter electrode potential or on the external parameters These conditional tests force the experiment to go to the next step loop to a previous sequence or end the sequence The aim of this manual is to describe every technique and application available in the EC Lab software This manual composed of several chapters The first is an
204. r several electrodes together in the electrochemical cell using a potential step Normal pulse voltammetry NPV technique used in analytical electrochemistry to discriminate faradic from capacitive current This technique is made of increasing pulses with time that always come back to the beginning potential Open Circuit Voltage OCV technique that consists of a period during which no potential or current is applied to the working electrode The cell is disconnected and only the potential measurement is available Pause Button of the EC Lab main window that leads to a suspension in the progress of the technique and in the measurement recording The cell is disconnected OCV period The Pause button switches to Resume when clicked 210 Techniques and Applications Manual Polarization resistance PR technique of general electrochemistry that can also be used in corrosion monitoring This technique allows measurement of polarization resistance R and corrosion current Icorr through potential steps around the corrosion potential Potentiodynamic cycling with galvanostatic acceleration PCGA Battery technique designed for battery cycling under stepwise potentiodynamic mode The user can reduce the potential step duration if the charge or discharge is lower than a given value Potentiostatic impedance PEIS technique that performs impedance measurements into potentiostatic mode by applying a sinus around a potential E that can
205. r to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range Bandwidth sets the current range and bandwidth values for the whole experiment Note It is highly recommended to not use the automatic current range with pulsed techniques The resolution of each range is different and dynamic current range changes may lead to have spikes on the plot NPV recorded and calculated variables The variables below are stored into the NPV raw files mpr State byte time s control V g Ewe V lt l gt mA Q Q mA h And the next variables are calculated from lt I gt or from the potential to save size on disk forward mA lt l gt values at the end of the pulses lp reverse mA lt I gt values before the pulses lbp delta pA difference between lt I gt values before and at the end of the pulse I lbp E step V step potential value resulting from the potential sweep and used to plot the current 2 3 5 RNPV Reverse Normal Pulse Voltammetry The Reverse Normal Pulse Voltammetry is a derivative technique from the NPV The main difference is that the initial base potential E is placed in the diffusion limited region for electrolysis of the species present in the bulk solution The pulses are made through the region where the species in solution is not electroac
206. ration of the imposed current period The sign of the current value is for a discharge and for a charge when the positive electrode of the cell is connected to the working electrode cable red enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment I Range and Bandwidth fixes the current range and bandwidth for this experiment Record Ewe every dE mV and at least every dt S allows the user to record the working electrode potential with a given potential resolution whenever the change in the working electrode potential is gt dE or and at least every dt time interval 2 Potentiostatic period Limit Ewe lt Ey V fixes the limit of the working electrode potential under charge discharge see warning 1 and stand for ty eee mn s or until I lt je ates pA A allows the user to stand at the potential Ey for a given time or until the current reaches a low limit value ly If the limit potential Ey is not reached within the time t or if ty is set to 0 the system skips to the next step Record AQ every dQ mA h and at least every dt S in the constant potential mode the system acts as a coulometer and a recording is performed every time the charge increment decrement since the previous recor
207. rcalation electrodes Report to the GCPL application section for more information on the other blocks The process option is the same as for the GCPL application 3 1 6 GCPL5 Galvanostatic Cycling with Potential Limitation 5 A parameter commonly used by industrial battery manufacturers is the Apparent Resistance of the cell This parameter called R is considered by each manufacturer like an internal characteristic for their cell The R value is determined by the ratio dE dl when a current step is done The manufacturers determine R values at different time after the current step depending on their instrument s time base So it becomes difficult to compare Ri values between different manufacturers R determination is now available in EC Lab software using a GCPL application refer to the process data section in EC Lab software manual and to the GCPL application section 3 1 2 page 90 for more details In fact Ri values are determined just after the current step according to the time Current and potential values are recorded with geometric progression of time in order to have a good distribution of points versus time Report to the GCPL section for more details 100 o 2 aetlto Is for at most t4 Limit Ewe gt Epa Record up to tmay Techniques and Applications Manual a wa om 10 hilo mm don 4 200 V 20000 s with geometric progression of time and then every dE or dty Hold Ep for tpg Limit I lt Im
208. re report to the ZRA for more details on the ZVC technique 169 Techniques and Applications Manual Fig 151 ZVC detailed diagram 170 Techniques and Applications Manual 3 4 Custom Applications 3 4 1 MUIC Measurement of U I Correlations This technique is an example of a special application tailor made for one of our customers lt records the potential fluctuations of a working electrode vs a reference electrode at the same time as the random current between the working electrode and the counter electrode which are connected through a low value resistor acting as the measurement shunt resistor Analysis of the correlation functions between Eye and gives information on the type of corrosion attack This technique takes advantage of synchronous measurement of Ewe and using the two ADC lines Operating this technique requires a specific VMP to cell cable with the shunt resistance being placed at the cell connection Rest fotp p hg mn 0 00 Record Ewe ever dERw 5 0 ri Epeevery dEfc 20 rv lever dl i n ggg and at least every d 10 With resistance 5 C Fig 152 Detailed diagram for U I correlation measurement 3 4 2 PR Polarization Resistance The polarization resistance can be used in several electrochemical techniques such as corrosion monitoring or general electrochemistry This technique makes measurement of the polarization resistance R of a material and Ico through potential steps
209. rent step block or to the previous measured current Imeas This option is not available on the first sequence N 0 To select the current step type check the option box for t fixes the current step duration 130 3 3 3 3 1 Techniques and Applications Manual limit Ewe lt Ey 000 mV and AQ lt AQy fA h A h pC KC curtails the step duration if the potential or charge limit is reached If the limit is reached the loop condition go to Ns for n times if set is not used and the program continues to the next sequence N 1 The AQ value is the integral charge for the current sequence This value is not reset if there is a loop on the same sequence Ns N 0 values disable the tests Record Ewe or lt Eye gt every dE mV and at least every dt S defines the recording conditions during the potential step O values disable the recording condition and the corresponding box stays green These values can be entered simultaneously and this is the first condition that is reached that determines the recording Range Bandwidth selects the current range and bandwidth values for the whole sequences e Loop goto sequence Ns for nc gonceeeeses time s gives the ability to loop to a previous sequence Ns lt N for n times Sequences of the chronopotentiometry technique can be chained using the Table frame The first sequence is
210. resistor by the energy device The constant resistance control is made by controlling the current to maintain the constant ratio E I 124 Techniques and Applications Manual 7 100 T 120 000 0 3 If Ewel gt EL pas goto 1 BO Fig 114 CLD detailed diagram e first step definition of the resistance and choice of recording conditions Start Discharge on R E I Ohm kOhm Mohm for at most ty h mmn S sets the cell resistance to R E I for ty duration With I Range and Bandwidth fixes the current range and bandwidth for this experiment Record every dE mV dq mA h and dt S defines the recording conditions These values can be entered simultaneously the first condition that is reached determines the recording A zero value disables the recording for each criterion Until Ewe lt Ey V AQ gt AQy mA h lt gt AXy Fixes the limit of the working electrode potential Ewe and the charge from the beginning of the sequence AQ Ax for the whole step The maximum charge can be entered into mA h AQ or as a normalized charge related to intercalation electrodes Axy Once a limit is reached the experiment proceeds to the next step Rest even if the programmed time ty is not terminated These limits can be bypassed by entering 0 values into the controls 125 Techniques and Applications Manual Note when
211. rocess F Allow Reprocessing Cycles detinition auto Esport s Text Compact Count half cycles DONE Display Close Fig 83 Process window for PCGA technique The X variable is obtained by processing the PCGA raw data file but without compacting it X can be processed if the user has previously defined the cell characteristics If the user has forgotten it it is still possible to modify the cell characteristics after the experiment in the raw data file In the Tools menu select Modify cell characteristics Open the desired raw data file and the cell characteristics window appears Once the characteristics are changed click on Save 89 Techniques and Applications Manual 3 1 2 GCPL Galvanostatic Cycling with Potential Limitation This technique corresponds to battery cycling under galvanostatic mode essentially i e with an imposed current but with possible potential limitations under current for both charge and discharge and tests on potential values during open circuit period At the user s convenience the potential limitations can lead to different options e Skipping to an open circuit potential period or to the next imposed current sequence e Switching from imposed current mode to imposed potential mode by maintaining for a given time the potential of the working electrode at the limit potential once it is reached Initial Rest Potential Sequence Ns 0 t JIA CAM ow To Ns
212. rrent to maintain the constant ratio E I 107 Techniques and Applications Manual 7 100 T 120 000 0 3 If Ewel gt EL pas goto T BO Fig 97 CLD detailed diagram first step definition of the resistance and choice of recording conditions Start Discharge on R E l Ohm kOhm Mohm for at most ty h mmn S sets the cell resistance to R E I for ty duration With I Range and Bandwidth fixes the current range and bandwidth for this experiment Record every dE mV dq mA h and dt S defines the recording conditions These values can be entered simultaneously the first condition that is reached determines the recording A zero value disables the recording for each criterion Until Ewe lt Ey V AQ gt AQy mA h lt gt AXy Fixes the limit of the working electrode potential Ewe and the charge from the beginning of the sequence AQ Ax for the whole step The maximum charge can be entered into mA h AQy or as a normalized charge related to intercalation electrodes Axy Once a limit is reached the experiment proceeds to the next step Rest even if the programmed time tm is not terminated These limits can be bypassed by entering 0 values into the controls 108 Techniques and Applications Manual Note when the AQy Axx limit is reached the E test is skipped This is due to the fact that the AQy
213. ry every 200 us for the VMP3 VMP2 VSP SP 150 and the BiStat and 20 ms for the VMP and the MPG Limit AQ to AQy fA h A h pC kC and to Imax pA A and to Imin pA A sets limits for the potential step If one limit is reached AQ gt AQy gt Imax or lt Imin before the end of the step duration t then the program goes to the next sequence A zero value disables the AQy limit and type p to enter pass to disable Ina and Imin limits Note the AQ value tested here versus AQy is the current sequence N integral charge And Analog In 1 Analog In2 lt gt L Vfort S sets limits of the sequence considering the value recorded with the analog input If the value reached L during t then the sequence is stopped and the next sequence is applied 185 Techniques and Applications Manual a eo 4 aE aq 4 1 000 o oo o oo o oo o o00 pass pass o oo 4 ela F A lj 4 D Go back to sequence Ng lo ACIS ate fae for mg lo tires E AVA A TRETE Fig 167 Special Modular Potentio potentiodynamic detailed diagram e Potentiodynamic Mode 2 Scan Ewe from E V vs Ref Eoc Ectrl Emeas to E V vs Ref Eoc Ectrl Emeas defines the initial potential E to a FIXED value vs Ref the reference electrode potential or RELATIVELY to the previous sequence final open circuit potential Ec or controlled potential Ect Or measured potential Emea
214. s and defines the final potential E in absolute vs Ref the reference electrode potential or relatively to the open circuit potential Esc or to the initial potential E 186 Techniques and Applications Manual With Linear Logarithm Exponential Polynomial scan defines the potential scan speed and its mathematical expression Anda b c d e defines the parameters of the mathematical expression enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment I Range and Bandwidth fixes the current range and the bandwidth for this experiment Record I lt l gt every dl pAl uA A dQp fA h A h pC kC and dtp s two different recording conditions on current are available with the potentiodynamic mode either recording an averaged current lt l gt on each potential step or recording an instantaneous current with an instantaneous current variation dl and or charge variation dQ and or a time variation Limit IAQI to AQy fA h A h pC kKC and to Imax pA uA A and lmin PAS UAl A sets limits for the potential step If one limit is reached AQ gt AQy gt Imax or lt Imin before the end of the step duration t then the program goes to the next sequence A zero value disables the AQy limit and type p to enter pass to disable Ina and Imi
215. s the number of points recorded per potential steps that will be recorded every At n seconds Note that lt l gt average current between 2 recorded points is stored into the data files for this technique So if one sets n 1 there will be only one point per potential step with the average current of the step However it is recommended to record several points per step because the associated process described below is able to skip the first points where the current may be perturbed by the potential step establishment enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range and Bandwidth sets the Range and Bandwidth for the whole experiment Note that the bandwidth does not perform any action on the measures but acts on the instrument s control loop to establish the potential e Open Circuit Voltage The open circuit voltage is the standard block so report to the OCV technique chapter for more information e Reverse potential step s Apply a second set of potential step s with reverse sign on AE lf checked then it will perform the potential steps again then with AE e Repeat Repeat ns time s repeats the whole sequence n time s Note that the number of repeats does not count the first sequence if N 0 then the sequence will be done 1 t
216. se the CPT with the VMP3 or VSP the user must have a temperature control unit equipped with potential analog inputs outputs to receive the control in potential and to send the measured temperature to the instrument We will give a detailed list of compatible TCU Our instruments can be configured at the user s convenience to display and directly control the analog potentials as temperatures in the External Device configuration window 149 Techniques and Applications Manual 3 3 9 2 MINISTAT Thermostat Cryostat circulating bath Among the compatible TCU units on the market most of them can be controlled with a 4 20 mA current For example The Ministat is a thermostatic bath with circulating fluid It can be operated manually or under control of the VMP TCU unit It reads and controls the temperature of the circulating liquid between 25 C and 120 C It can be connected to several serially coupled jacketed electrochemical cells The temperature of each individual cell is monitored by the TCU with a PT100 temperature sensor to provide accurate 0 15 C temperature reading of the electrolyte inside the cell For the potential control the compatible TCU unit with circulating fluid must be equipped with an analog card not standard with the systems Compatible units are Julabo HL SE HE and SL series Haake Phoenix series Neslab EX series Fig 133 PT 100 temperature sensor 7 mm L 200 mm cable 2 m F
217. seq Ns p HGS ante acta for mge E time s TAVIE ARASA Ne 40l 1 2 3 4 5 6 7 8 9 10 Fig 111 PWPI detailed diagram e Pulsed power discharge Set power to P mW KW for t h nann Mn S define the restance pulse value and duration Record Ewe every dE mV and at least every dts S limits the recordings conditions in voltage variation and or time variation I Range and Bandwidth fixes the current range and bandwidth for this experiment e Conditional test which proposes to go to the next sequence or to loop on a previous sequence Ng Ns lt Ns Photovoltaics Fuel Cells This section is especially dedicated to energy devices not requiring any charge sequence They are studied only in the discharge mode fuel being for these devices a gas or the sun light This section includes five different applications the V characterization the constant load discharge the constant power voltage and current 121 Techniques and Applications Manual Insert Techniques 4 9 Electrochemical Techniques o p ee Yoltamperometric Techniques gt tom Impedance Spectroscopy gt Pulsed Techniques gt Ag Technique Builder gt Manual Control b45 Ohmic Drop Determination 44 Electrochemical Applications gt H 3 Batteries Testing a ogy Photovoltaic Fuel Cells Hy A characterization VC Constant Load Discharge CLD Constant Power CP TL Co
218. sibility to determine the solution resistance R for one high frequency value The user can select the percentage of compensation It is highly recommended to not exceed 85 of the Ry measured value to avoid oscillations of the instrument To compensate the solution resistance the user has to put this ZIR technique before other experiments in a linked experiments series by this way R value will be automatically considered before each experiment of the series This technique is very close to the Potentiostastic Impedance technique PEIS except that the EIS measurement is made for only one frequency So report to the PEIS experiment section for more details SetEweto E 00000 vs Eoo l Calculate IA with PEIS method at f 100 000 khe i anus amplitude Ya 20 0 rei walt for Py 0 10 pernod before measurement average Ny 4 measurels Fl compensate at 35 a ERange 25 25 Areca Fade Range Auto 7 Bandwidth SO 2 scan Fig 75 ZIR diagram e Impedance scan 80 Techniques and Applications Manual Set Ewe to E V vs Ref Eoc Ectrl Emeas sets the potential to a fixed value E vs Ref the reference electrode potential or relatively to the previous OCV potential Eoc controlled potential Eet measured potential Emeas Calculate IR with PEIS method at f MHz kKHz Hz mHz yHz defines the frequency to measure the resistance with an amplitude V mV sets the
219. stment Range Bandwidth The choice of the current range depends on the threshold pitting current value lp and is automatically fixed The bandwidth is selected by the user Once the threshold pitting current is reached the working electrode is disconnected The figure below Fig 145 shows the result of a potentiodynamic multi pitting experiment performed on 8 passivated stainless steel electrodes 0 060 0 055 0 050 0 045 0 040 0 035 0 030 j 0 025 f i 0 020 0 015 0 010 0 005 0 ee 0 000 ee lima 0 005 0 010 4 I I I I I 0 40 0 42 0 44 0 46 0 48 0 50 0 52 0 54 0 56 0 58 controls Fig 145 8 electrodes Potentiodynamic Pitting experiment Electrode Stainless steel in 0 02 M NaCl Scan rate 100 mV mn Recording resolution 0 2 pA or 20 ms 164 Techniques and Applications Manual 3 3 10 2 Data processing Data processing using Multi Pitting Statistics gives the mean values lt E gt and the mean quadratic deviations o of the final rest potentials Es and pitting potentials E obtained from all the channels used in the experiment Note that the E value corresponds to the potential measured for Ip Multi Pitting Statistics C Documents and Settingssebasten manips YMPI seb corosionshMPPSMPP4 1s mpr C Documents and Settingssebasten manips VMPII seb corosionshMPPSMPP4 1 4ompr C Documents and Settings sebasten manips YMPI seb corosionsMPPSMPP4
220. t lt dEp dt mV h stops the rest sequence when the slope of the open circuit potential with time dE dt becomes lower than the set value value 0 invalidates the condition Record Ewe every dEr mV resolution and at least every dtp S allows the user to record the working electrode potential whenever the change in the potential is gt dEr with a minimum recording period in time dtr Data recording with dEr resolution can reduce the number of experimental points without loosing any interesting changes in potential When there is no potential change only points according to the dtr value are recorded but if there is a sharp peak in potential the rate of recording increases enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment 2 1 2 CV Cyclic Voltammetry Cyclic voltammetry CV is the most widely used technique for acquiring qualitative information about electrochemical reactions CV provides information on redox processes heterogeneous electron transfer reactions and adsorption processes It offers a rapid location of redox potential of the electroactive species Techniques and Applications Manual CV consists of linearly scanning the potential of a stationary working electrode using a triangular potential waveform During the potential sweep the potentiostat measures the current r
221. t T back to Ti Fig 141 Detailed diagram of the CPT2 technique 159 Techniques and Applications Manual The whole sequence can be described with the following figure IeasurED Fig 142 I Eye and T vs time for the CPT2 experiment e First step set the initial temperature and turn to rest The initial temperature block is identical to the CPT initial temperature block so report to the CPT technique chapter for more information e Second step potential scan Keep T Ti during this step the temperature is maintained to the value defined in the first step Scan Ewe with dE dt mV s fixes the scan rate dE dt in mV s The software automatically adjusts the step amplitude and its duration The potential and the time step values are multiples of 100 uV and 20 ms respectively The minimum 100 uV step amplitude and 20 ms potential level duration gives a 5 mV s scan rate From Ei V vs Ref Eoc Ectrl Emeas to E V vs Ref Eoc Ei from a potential E defined in absolute vs Ref the reference electrode potential or versus a previous open circuit potential Eoc previous controlled potential Een or previous measured potential Emeas to Ep value defined in absolute or versus Eg or Ei Record e lt I gt over the last of the step duration averaged N voltage steps el every dl WA or dt S 160 Techniques and Applications Manual two different recording conditions
222. t each slave channel will measure the voltage of two elements as follow E1 Ref1 Ref2 E2 Ref2 Ref3 As an example with the picture above the master channel is ch3 and the unit has 5 channels to follow the slaves so the total amount of measured elements in the stack is 10 But the stack can be constituted with more than 10 elements Only 10 elements will be measured in this configuration On the slave channels the current wires CA1 and CA2 are not used Note also that most of the techniques and applications can be used and linked in Stack mode When the user clicks on the Ok button the Techniques selection window is automatically displayed At this step the user can create the experiment with one or more techniques When the connection is done and the channels master and slave selected the user has to click on the ok button The technique selection window Is displayed All the techniques in EC Lab can be used and linked in the stack mode When an experiment is run on a stack the master channel measurement is displayed on one graph and the slave channels curves are displayed together on a separate graph Here after are several examples of stack measurements 200 Techniques and Applications Manual a Rog xs peis 5 with R mpr lmi21 vs Re 1 m 42 vs Re z2 lm 43 vs Re 23 Im 4 vs Re Z4 lm 25 vs Re 5 Im 25 vs Re 26 Imir vs Rel m 23 vs Re 43
223. t versus which the cell current will be applied Eu Maximum potential limit dE Recording condition on a variation of potential dt Recording condition on a variation of time fj Initial frequency fi Final frequency Na Number of points per decade N Total number of points l Sinus current amplitude Na Number of averaged measures per frequency Vep Peak to peak potential amplitude l Final current value N Number of current potential steps 206 Techniques and Applications Manual Final potential value Uncompensated resistance Compensated ohmic drop Pulse height Pulse Width Step height Step time Pre Pulse Width Pre Pulse Height Pulse period Period duration Step potential Time duration of Es Waiting duration Sequence to go back to with a loop Number of iterations of the experiment 207 Techniques and Applications Manual 8 Glossary This glossary is made to help the user understand most of the terms of the EC Lab software and the terms mentioned in the manual The terms are defined in alphabetical order Absolute value mathematical function that changes the negative values in positive ones Accept button in EC Lab software that switches to Modify when the user clicks on Modify must be displayed to run the experiment Apparent resistance Rj conventional term defining the electrolytic resistance in a solid electrochemical system such as a battery R is defined as the ratio dE dl when the pote
224. te measurements This leads to the determination of redox potential and kinetic parameters The External Device Configuration of EC Lab menu makes easy to control and measure the rotating rate of the R R DE device Rest fort p o ho m BO Limit dE werdt lt dEp dt 90 mwh Record every dEp Oo oi or dtp o1000 3 Scan Ewe with dE dt i 00 000 mig from Ej Do WV ve Eoc to EL 2000 vs Rel hl Record m over the last 50 Of the step duration average HN i T voltage steps ERange 25V 25V Greaney Aa a Range Auto Bandwidth 5 m dE dt 100 py 47 0 ms GEN 1 0 m Fig 7 Linear Sweep Voltammetry detailed diagram e Rest period Rest for tr h mn S fixes a defined time duration tp for recording the rest potential or until dE dt lt dEp dt mV h stops the rest sequence when the slope of the open circuit potential with time dER dt becomes lower than the set value value 0 invalidates the condition Record Ewe every dEr mV or dtg S allows the user to record the working electrode potential whenever the change in the potential is gt dEr with a minimum recording period in time dtr e Potential sweep with measurement and data recording conditions Scan Ewe with dE dt mV s allows the user to set the scan rate in mV s The potential step height and its duration are optimized by the software in order to be as close as possible to an analogic scan Betwee
225. ted over the entire metallic surface The corrosion rate is nearly constant at all locations Microscopic anodes and cathodes are continuously changing their electrochemical behavior from anode to cathode cells for a uniform attack 139 Techniques and Applications Manual This technique corresponds to half a cycle or one cycle of usual cyclic voltammetry with the particularity of a digital potential sweep i e it runs by potential steps defined and periodic in amplitude and time For the VMP3 VMP2 VSP SP 150 BiStat and the SP 300 the potential step and its duration are defined according to the potential control resolution see the EC Lab software manual for more details For the VMP the minimum amplitude of the potential step is 100 uV and its minimum durations is 20 ms Then the particular value for the scan rate is 300 mV min 5 mV s Lower scan rates will be obtained with longer step duration whereas higher scan rates will be obtained with higher step amplitudes If the user specifies a scan rate the system proposes the closer value that can be obtained with adequate multiples of the potential and time resolutions 100 uV 20 ms or 100 uV 10 ms In the present version of this application the result file contains the mean value of the current measured for the whole potential step duration This mean value is the result of measurements carried out every 2 ms Begin End E3 Fig 126 General diagram of the Gener
226. tential Limitation 2 GCPL2 Galvanostatic Cycling with Potential Limitation 3 GCPLS Galvanostatic Cycling with Potential Limitation 4 GCPL4 Galvanostatic Cycling with Potential Limitation 5 GCPLS Galvanostatic Cycling with Potential Limitation 6 GCPLE Time Constant Load Discharge CLD Constant Power Cow This technique consists to apply various potential values on a batter during a defined duration This technique is specially Alternate Pulse Galvano Cycling APGC designed to fit with the urban driving patterns designed to test EW ane Patentio Profile Importation PPI batteries The particularity of this technique ts the large number of Head Galvano Protile Importation GFI sequences available and the fact that the esperimental settings can a Resistance Profile Importation RPI be defined by importation of a text file Note that experimental limits di Power Profile Importation PWPI are not present in the setting itis highly recommended to use safety limits located in the Advanced Setting window to avoid Photovoltaic Fuel Cells overcharge or overdischarge of the batteries Corrosion Text file imporation columna time s differential or absolute and gt Custom Applications potential Special Applications Insert Technique Load from default Custom Applications Before Advanced setting C External devices After Cell characteristics Bename Add Pigman Fig 106 Selection wind
227. ter the galvanostatic phase Report to the GCPL2 application section for a description of this application 97 Techniques and Applications Manual 1 Setlto le f00 000 im VB lt None gt for at most ty ho hilo mn Ooo Limits Ewe Ece gt EW 4000 Ewe gt ELw 4 200 Y Ece lt Elec 1 000 Record Ewe Ege every dEy B0 m or dty 60 0000 Hn kf sgt Ef boats ae ie A Set Ewe Ereto Eg Bo forte 7 bio mn pooo0 Limit M lt IM 0000 ma Record evey dq 000 m h 7 odtg 30 0000 Limit AQI gt AQM 0000 mh lt gt AtW O00 ERange gwy 5w Arena Aa ri Range 100 m Bandwidth 7 2 RestiootR f2 hf mn joon s Limit IdE wedt lt dERfdt 00 rv A Record even dep oo rity odt 30 0000 itt Oe AG Ady goto EY 3 WEwe Ece lt EL 400 V goto 1 4 Gobackto seq Mgt f RGIS anh facie fo ne 3 time s Sian aes MANANE Ne o fi 2 Fig 90 GCPL3 detailed diagram 3 1 5 GCPL4 Galvanostatic Cycling with Potential Limitation 4 The GCPL4 application is similar to the GCPL application but with the global time limitation for the charge discharge period 98 Techniques and Applications Manual 1 Setlto le 100 000 m VE lt None gt Limit Ewe lt EM 3200 Record even dE 50 mi o dt 30 0000 Hold Epg once reached Limits I lt Im fig 000 m goto 2 I Tle retum to l
228. th amplitude Py and duration Sr Notice that only one point is recorded at the end of the potential forward pulse and one point at the end of the potential reverse pulse making two points during the S period The settings above Fig 45 are given for a positive scan To perform a negative scan set E inferior to E and Sy to a negative value 56 Techniques and Applications Manual Scan rate mV s number of points These values are given as an indication and are calculated in the PC The scan rate is directly given by S 0 001S and the number of points is roughly 2 E E S for the forward scan average over the last Of each step points Selects the end part of the potential step for the current average lt I gt calculation to exclude the first points where the current may be disturbed by the step establishment A value of 100 will take all the step points for the average and a value of 0 will take only the last point Note that the current average lt I gt is recorded at the end of the potential step into the data file E Range enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment IRange Bandwidth sets the current range and bandwidth values for the entire experiment Note It is highly recommended to not use the autom
229. th the following rules experiment file name user file name _ experiment number short name _ channel number mpr experiment For example the user file name MyFileName will be used to generate the following files experiment 1 no file name for the Trigger In option experiment 2 MyFileName_2 MP_01 mpr experiment 3 MyFileName_3_WAIT _01 mpr experiment 4 no file name for the technique linker loop Each of these files will store the corresponding data points for all the loops Note it is possible to synchronize linked experiments on several channels Application Once the file name has been entered the acquisition starts and the program shows the graphic display with the data files 196 Techniques and Applications Manual During the run the running technique can easily be identified by the green color around the corresponding button Its number is displayed in the running experiment box see next figure in Run Tec The number of loops executed is displayed in Tec Loop As for a single experiment run it is possible to Pause Resume and Stop the acquisition The Stop button will terminate the whole experiments acquisition Nevertheless one can stop the current experiment and continue to the next one with the Next Exp button ve in the tool bar Channel 1 values EJ 0 090 m Ewe 0 205 W Time 001 27 1274 Eo 0 157 m Status Tsidation Butter 1 O Qo 22 14 n h Range 100 p Nes nc
230. the AQy Ax limit is reached the E test is skipped This is due to the fact that the AQy limit is considered as the maximal charge that can be applied to the energy device during the discharge Once reached the experiment must go to the next sequence 3 2 8 CPW Constant Power The Constant Power application is designed to study the discharge of an energy device at constant power The constant power control is made by checking the current to maintain the E l constant The current increases when Ewe decreases Fig 115 CPW detailed diagram first step choice of the power value Set P E l uW mW W for at most ty Msoi mn S sets the cell power to P E I for ty duration 126 Techniques and Applications Manual With I gt 0 or I lt 0 and keep I lt Iy pA A defines the charge I gt 0 or discharge I lt 0 mode and limits the current to a maximum value Iy in order to preserve the cell and or the instrument With I Range and Bandwidth fixes the current range and bandwidth for this experiment Record every dE mV dq mA h and dt S Define the recording conditions These values can be entered simultaneously The first condition that is reached determines the recording A zero value disables the recording for each criterion Until Ewe lt Ey V AQ to AQy MA h lt gt AXy E vee fixes the limit of the working electrode potential
231. the above 3 steps will be repeated until the working electrode potential reaches the limiting condition Ewe E after a charge or Ewe lt E after a discharge Note the user is allowed to bypass this test by entering p pass instead of a voltage value e Fourth step repeat sequences The fourth step fixes the next sweep by filling the Ns and n variables as seen in tutorial 2 for the GCPL technique setting Ns to a previous sweep and n to the number of repeats will loop ne times to Ns Setting n to O will go to the next sweep or will end the technique on the last sweep Setting Ns to 9999 will stop the technique at the end of this sweep A sweep corresponds to a line in the table The columns represent the successive values for variables of the diagram the current range the bandwidth settings and the loop conditions The current range and bandwidth settings are obtained either with a double click on any cell of the corresponding columns or directly in the cell characteristics window Warning see also GCPL Warnings 1 and 2 when running a charge cycle positive potential sweep the value of the electrode potential for the test E must be set at a lower value than the sweep limit value E Similarly when running a discharge cycle negative potential sweep E must be set at a more positive value than the sweep limit value Er The cell characteristics window for battery testing applications has been previously described
232. the previous two sequences to calculate an averaged resistance value o Compensate at defines the level of the measured uncompensated resistance R that will be compensated to define IR The user can check the box to consider the compensated resistance in the following technique or not Calculate Ri at Both Rising Falling edge Do the resistance calculation for either the rising edge or the falling edge or both of them 82 3 1 1 Techniques and Applications Manual Electrochemical applications Battery In this application domain it is usual to run a succession of charge and discharge sequences with possible open circuit periods varying the conditions for the cycles The techniques are defined on the basis of controlled mode and open circuit mode The controlled variable is either the potential or the current A controlled current event is called a sequence whereas a controlled potential is labelled as a sweep Such a sweep or sequence appears as a line in the parameter value table associated with the technique The user can set the variable values directly in the table or can set them in the diagram After a first specific sequence or sweep Ns 0 which enables the user to perform an open circuit period while recording only the potential no controlled value can be set in this first sequence sweep the technique executes the successive Ns sequences sweeps of the table lines It is possible to run partial cycling before
233. the rate of the potential recording is governed by the potential recording resolution e Second step potential scan Scan Ewe with dE dt mV s defines the potential scan The software selects the smallest potential step according to the control potential resolution defined at the top of the Parameter settings window see the corresponding section in the EC Lab software manual for more details From Ei V vs Ref Eoc Ectrl Emeas to E V vs Ref Eoc Ei from a potential E defined in absolute or versus a previous open circuit potential Esc or previous controlled potential Es or previous measured potential Emeas to Ep value defined in absolute or versus Eg or Ei Record lt I gt over the last of the step duration averaged N voltage steps every dl pA nA pA mA A or dt S Two different recording conditions on the current are available with the potentiodynamic mode either recording an averaged current lt I gt on each potential step or recording an instantaneous current with a time variation and or an instantaneous current variation dl and or charge variation dQ enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment Range and Bandwidth defines the current range and bandwidth for the whole
234. tial resolution whenever the change in the working electrode potential is gt dE or and at least every dt time interval 2 Potentiostatic period Limit Ewe lt Eu V fixes the limit of the working electrode potential under charge discharge see warning 1 and stand for ty Misseivens mn s or until I lt Pe N pA A allows the user to stand at the potential Ey for a given time or until the current reaches a low limit value ly lf the limit potential Ey is not reached within the time t or if ty is set to 0 the system skips to the next step Record AQ every dQ mA h and at least every dt S in the constant potential mode the system acts as a coulometer and a recording is performed every time the charge increment decrement since the previous recording is gt dQ and or every dt time interval Limit AQ to AQy mA h lt gt AXy fixes the maximum charge change from the beginning of this sequence during the sequence This charge is equivalent to a Axy quantity which corresponds to a normalized charge related to intercalation electrodes And Analog In 1 Analog In2 lt gt L Vfort S sets limits of the sequence considering the value recorded with the analog input If the value reached L during t then the sequence is stopped and the next sequence is applied e Second step open circuit period with monitoring of the electrode potentials turn to Rest for tp
235. ting Ru value is calculated Averaged values can be determined on several cycles The user can select the percentage of compensation It is highly recommended to not exceed 85 of the Ru measured value in order to avoid oscillations of the instrument E3 E we E gt E E 4 lz I3 l l4 T t Fig 76 Current Interrupt principle 81 Techniques and Applications Manual Set I 200 000 m for t 0 050 0 z Record every dE i D mi dt 00002 3 ERange 10W 10Y fam PTAR a r Range f A Bandwidth S medium Tum to Oly for tR 0 050 T F with the same recordings Repeat and UCY blocs ne 10 tire Z compensate at 60 Yo Calculate Ay at Both Aisin Falling Fig 77 Current Interrupt detailed diagram Set pA Afort sS sets the current to a fixed value Record every dE mV and dt s chooses one or several optional recording conditions enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software user s manual for more details on the potential resolution adjustment Range Bandwidth sets the current range and bandwidth values for the whole experiment Turn to OCV for tp s with the same recordings Turn to the OCV mode for a given time with the same recording conditions as the galvanostatic block Repeat and OCV blocks nc times Repeat
236. tion Rest Potential Sequence The open circuit voltage is the standard block so report to the OCV or GCPL techniques chapters for more information Test Ewe gt EL Tests that the battery is charged or discharged For a proper run of this test one must ensure that gt lo then if h lo Ewe lt E oxidation then the galvano pulse is performed again else the execution continues to the next sequence if h lt lol Ewe lt E reduction then the galvano pulse is performed again else the execution continues to the next sequence If the OCV period is canceled tr 0 or the Emin Emax Or AQ limits have been reached then the E test is not performed If the user types the p character for pass for E then the test is skipped too Next sequence Next sequence or Goto sequence N for ne time s loops to a previous sequence Ns lt Ns Nne time s Set n O to cancel the loop and go to the next sequence N 1 Note in this technique the first and last data points of each current steps are not recorded automatically 116 Techniques and Applications Manual 3 1 11 PPI Potentio Profile Importation Insert Techniques gt fr Potential gt fe Manual Control gt fe Ohmic Crop Determination 4 4 Electrochemical Applications enes Testing Potentiodynanic Cycling with Galyanostatic Acceleration PEGA Galvanostatic Cycling with Potential Limitation ACFL Galvanostatic Cycling with Po
237. tion adjustment Range and Bandwidth Defines the current range and bandwidth for the whole experiment Range is automatically set according to and l values Pitting I gt h for t gt ta or T C reached M Stop Controlling T O Set T C If pitting or temperature Te is reached then it stops controlling temperature TCU control 0 mA or applies a final temperature T and stops the experiment Otherwise go to the third step e Third step increase temperature and turn to rest Increase T with T C below T C and T z C above Increases the temperature with Ts or Ts2 according to the TL value This allows for bigger steps in temperature with each cycle that pitting is not reached in order to speed up the experiments total duration Rest Until lt dT dt gt lt dT C 7 dh Shu h mn or fort Miissi mn rest parameters see first step Record every dT C dEr mV and dtp mn S IF dT dt and t are set to 0 than the rest will not be executed but the temperature will be increased and the experiment will restart at the second step without the potential scan This means that the potential Ep will be applied continuously for the rest of the duration of the pitting experiment 3 3 9 5 CPT2 technique The CPT2 technique is exclusively reserved to the VMP Before running any CPT2 experiment one must f
238. tions Manual SetEwe to Ej 0 400 Wows Ref 4 fort D hip mh ooooo Apply waveform with prepulse height PPH 500 mi prepulse width PP 250 ms pulses height PH foo m pulse width Pw foo ms Fig 52 DPA waveform pulse period P Aoo ms forty O hfo ma Do0 average ower the last i oo ofeach pulse rAr men PATUN ov een TEAT E Ranges 2y 2W Bel ean Fade Range 0 pa 7 Bandwidth z Fig 51 DPA detailed diagram Description e Initial potential Set Ewe to Ej V vs Ref Eoc Ectril Emeas fort h mn S sets Ewe to the initial potential E This potential value can be set in absolute vs Ref the reference electrode potential or according to the previous open circuit potential E c controlled potential Ear or measured potential E meas Notice that only the last point of this period is recorded at the time 0 e Pulse waveform Apply a waveform with the following characteristics Prepulse height PP mV Prepulse width PPy ms Pulses height Py mV Pulse width Py ms Period P ms Time period tp ms Noticed that only one point is recorded at the end of the potential forward pulse and one point at the end of the potential reverse pulse making two points during the P period number of points This value is given as an indication and is calculated in the PC The number of points is roughly 2 t P for the forward scan average over t
239. tive The RPV experiment involves a significant faradic current This method is a reversal experiment because of the detection of the product from a prior electrolysis 59 Techniques and Applications Manual SetEweto Ey 0500 vs Ref gt forty 0 hi mn fon ScanEwe from Ejto Ey 0500 vs Ref gt with pulses height PH fog mv pulses width Py 250 ms step time ST 1000 ms average over the last i Ooo 2 ofeach step Ath mwi nee aa RTE aes AAAS cao It ERange 24 2 Greaney Fag Range 10 m 7 Bandwidth 7 m Fig 50 RNPV waveform Fig 49 RNPV detailed diagram Description e Initial potential Set Ewe to E V vs Ref Eoc Ectril Emeas fort errr mn S sets Ewe to the initial potential E This potential value can be set in absolute vs Ref the reference electrode potential or according to the previous open circuit potential E c controlled potential Ear or measured potential E meas Notice that only the last point of this period is recorded at the time 0 e Pulse waveform Scan Ewe from E to E V vs Ref Eoc Ei defines the vertex potential as E either in absolute vs Ref or versus Eg or Ei with pulses height Py mV pulses width Py ms step time S1 ms The pulse train is made of pulses with a pulse height Py amplitude that is added to the pulse height of the previous pulse and a pulse width Pw duration After each pulse th
240. to loop on a previous sequence Ns Ns lt Ns lf n is set to 0 then the technique executes the next sequence If the user wants to loop to a previous sequence line he has to fill the 2 last columns of the table Go to Ns and n cycles The end of the technique is obtained by setting Ns and n to 0 in the last sequence or setting Goto sequence Ng 9999 at any sequence which then will be the last one executed even if the next sequence has its settings 3 1 12 GPI Galvano Profile Importation This technique consists to apply various potential values on a battery during a defined duration This technique is specially designed to fit with the urban driving patterns designed to test EV batteries The particularity of this technique is the large number of sequences available and the fact that the experimental settings can be defined by importation of a text file Note that experimental limits are not present in the setting it is highly recommended to use safety limits located in the Advanced Setting window to avoid overcharge or overdischarge of the batteries The text file importation columns are time s differential or absolute and potential V Record Ewe even des 0 0 mi and at least ewer dts 0 1 mma Gobackto seq Ns 0 GES enage facies for nge 0 limes ao ase wage Fig 109 GPI detailed diagram e Pulsed galvano Charge Set I to I V fort h MN S define the current pulse
241. to loop to a previous sequence line he has to fill the 2 last columns of the table Go to Ns and n cycles The end of the technique is obtained by setting Ns and n to 0 in the last sequence or setting Goto sequence Ng 9999 at any sequence which then will be the last one executed even if the next sequence has its settings Such a complete sequence corresponds to one line of the table This line is composed of the columns which represent the successive variables encountered when setting the diagram the current range and the loop conditions all parameters which has to be set by the user Note that it is always possible to force the end of a technique while it is running at any sequence sweep using the Modify button and setting Goto sequence Ns 9999 at the sequence one wants to stop 193 Techniques and Applications Manual Linked experiments Description and settings It is possible to link different techniques within the same run This allows the user to create and build complex experiments with up to 20 techniques When created the linked experiment settings can be saved either as a mps file or a Custom application In the first case the settings can be loaded from the initial folder and in the second case they appear in the applications and can be reloaded when necessary Linked experiments can be made using the technique builder in the technique window All the techniques of this section have been previousl
242. to the data file Record lt I gt averaged over N voltage step s averages N current values on N potential steps in order to reduce the data file size and smooth the trace The potential step between two recording points is indicated between brackets Once selected an estimation of the number of points per cycle is displayed into the diagram enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment Range bandwidth enables the user to select the current range and the bandwidth damping factor of the potentiostat regulation e Reverse scan Reverse scan towards vertex potential E V vs Ref Eoc Ei runs the reverse sweep towards a 2 limit potential The vertex potential value can be set in absolute vs Ref or according to the previous open circuit potential Esc or according to the potential of the previous experiment E Hold E for t h mn S and record every dt S offers the ability to hold the second vertex potential for a given time and to record data points during this holding period e Repeat option for cycling Repeat n times 13 Techniques and Applications Manual repeats the whole sequence n time s Note that the number of repeat does not count the first sequence if ne 0 then the sequence will be done 1 t
243. ts or damage resulting from any failure to comply with these precautions GROUNDING To minimize the hazard of electrical shock it is essential that the equipment be connected to a protective ground through the AC supply cable The continuity of the ground connection should be checked periodically ATMOSPHERE You must never operate the equipment in corrosive atmosphere Moreover if the equipment is exposed to a highly corrosive atmosphere the components and the metallic parts can be corroded and can involve malfunction of the instrument The user must also be careful that the ventilation grids are not obstructed An external cleaning can be made with a vacuum cleaner if necessary Please consult our specialists to discuss the best location in your lab for the instrument avoid glove box hood chemical products AVOID UNSAFE EQUIPMENT The equipment may be unsafe if any of the following statements apply Equipment shows visible damage Equipment has failed to perform an intended operation Equipment has been stored in unfavourable conditions Equipment has been subjected to physical stress In case of doubt as to the serviceability of the equipment don t use it Get it properly checked out by a qualified service technician LIVE CONDUCTORS When the equipment is connected to its measurement inputs or supply the opening of covers or removal of parts could expose live conductors Only qualified personnel who should re
244. ual for more details on the potential resolution adjustment I Range and Bandwidth fixes the current range and bandwidth for this experiment 2 4 1 4 Sequences with the Modular galvano technique The three modes of the Modular Galvano technique can be chained as sequences in the table in any order that the user requires Each of the parameters can be modified in its box However parameters like Range or Bandwidth must keep the same value for all the sequences Note that the first sequence has the number N 0 To switch from one sequence to another click on the desired row in the table For more details about the Table frame see the chronoamperometry technique p 19 Management of the various steps can be done thanks to sequence or table Fig 58 0 00 1 0000 0 0 0 5000 0 000 lt None gt 0 00 0 001 0 00 0 0000 0 0 0 0000 50 000 None gt 0 07 0 00 0 00 0 0000 0 0 0 0000 0 000 None gt 0 00 0 001 Hone Pan eat hl gt Fig 58 Modular Galvano table Note In this technique the first and last data points of each current steps are not automatically recorded 2 4 2 MP Modular Potentio The Modular Potentio technique performs OCV potentiostatic and potentiodynamic periods It is possible to chain these periods in any order and perform loops that provide great flexibility This technique is very useful because it allows coupling potential sweep detections with preconditioning steps either in OCV or
245. uce the number of experimental points without losing any interesting changes in potential When there is no potential change only points according to the dtr value are recorded but if there is a sharp peak in potential the rate of recording increases 3 3 2 LP Linear Polarization The linear polarization technique is used in corrosion monitoring This technique is especially designed for the determination of a polarization resistance R of a material and Ico through potential steps around the corrosion potential R is defined as the slope of the potential current density curve at the free corrosion potential _dE p dE 0 dI R is determined using the R Fit graphic tool This technique is also used to plot polarization curves and determine corrosion rate and coefficients with Tafel Fit 3 3 2 1 Description ali piee 0 025 pos 4 d n OS 4 dE dt 100 py 7 602 4 mes WEN 500 pi Fig 119 Detailed diagram of the Linear Polarization application e First step rest potential or open circuit sequence 132 Techniques and Applications Manual Rest for tp i ROER MN anaana S fixes a defined time duration tp for recording the rest potential or until dEwe dt lt dEp dt mV h gives the user the ability to shorten the open circuit period at the time when the decay of the potential is lower than a given value Record Ewe with dEp mV resolution and at le
246. uence for example will be programmed by 3 187 Techniques and Applications Manual lines into the parameters table Setting Nn gt 0 will loop to a previous line Ns lt Ns for ne times Go to the battery protocols section 3 1 page 83 for more details on loops conditions It is possible to loop to Ns 0 but N must be lt N current sequence line number B Lt mm fmm 5 mm i o 050 pss pass 0 0000 pass fo 3 Go back to sequence Ng lo HGS ate facie for yp D time s AAV AST A A E Fig 168 Special Modular Galvano Galvanostatic detailed diagram e Galvanostatic Mode 1 Set I tol pA A vs lt None gt Ictrl Imeas for t h Mn sets the current to a fixed value for t time The current value can be defined in absolute or versus a previous controlled current or measured current With I Range and Bandwidth fixes the current range and the bandwidth for this experiment Record every dE mV dt s and dQ fA h A h pC kC defines the recording conditions A zero value cancels the corresponding recording criterion These values can be entered simultaneously then this is the first condition that is reached that determines the recording For the galvanostatic mode dQ is not accessible and is calculated from and dt dQ ls dtp Limit Ewe to E V and AQ to AQy fA h A h
247. ulses width Py ms step time S1 ms The pulse train is made of pulses with a pulse height Py amplitude that is added to the pulse height of the previous pulse and a pulse width Pw duration After each pulse the potential always comes back to the initial potential The scan increment is defined by a pseudo staircase composed of steps with amplitude Py and duration Sr Notice that only one point is recorded at the end of the potential forward pulse and one point at the end of the potential reverse pulse making two points during the S period The settings above Fig 47 are given for a positive scan To perform a negative scan set E inferior to E and Sy to a negative value Scan rate mV s number of points these values are given as an indication and are calculated in the PC The scan rate is directly given by P y 0 001S and the number of points is roughly 2 E E S for the forward scan 58 Techniques and Applications Manual average over the last of each step points selects the end part of the potential step for the current average lt I gt calculation to exclude the first points where the current may be disturbed by the step establishment A value of 100 will take all the step points for the average and a value of 0 will take only the last point Note that the current average lt I gt is recorded at the end of the potential step to the data file E Range enables the use
248. ustment Range Bandwidth sets the current range and bandwidth values for the entire experiment Non stationary correction drift correction corrects the drift of the system This feature is more especially dedicated to low frequencies Note if this option is selected the sinus frequencies are evaluated over 2 periods instead of 1 increasing the acquisition time by a factor of 2 e Potential scan with definition of the number of potential steps Scan Ewe to E V vs Ref Eoc Ectrl Emeas With N potential steps dE mV define the potential sweep limit to E in either absolute or versus the open circuit potential the previous controlled or measured potential The user selects the number of potential steps from E to E and the step amplitude dE is displayed as information 47 Techniques and Applications Manual Graph tool Mott Schottky plot For the SPEIS technique particularly used in semi conductor materials study Mott Schottky experiments it is possible to display the 1 C vs Ey plot when selecting Mott Schottky in the rapid selection scroll menu This graphic display is available during the run because the capacitance values are automatically calculated during the experiment When the Mott Schottky plot is selected the user must choose several frequencies among all the recorded frequencies Moreover a special fit Mott Schottky fit has been built to determi
249. ution cannot lead to exact 5 mV steps because 85 Techniques and Applications Manual 9 0 3 16 67 is not a integer In that case the user will receive the following warning message Warning the potential step des is not a multiple of 300 py that is the potential control r solution vr Continue Fig 80 PCGA warning message for the step amplitude lf the user answers Yes the step will automatically be adjusted to 5 1 mV instead of 5 mV To perform exact 5 mV steps the potential control resolution must be adjusted report to the corresponding section in the EC Lab software manual for more details From E V vs Ref Eoc Ectrl Emeas sets the starting potential in absolute vs Ref the reference electrode potential or with respect to the final open circuit potential value of the previous sequence E or the previous controlled potential value Eem or the previous measured potential value Emeas It allows the experiment to start at the open circuit potential of the battery to E V vs Ref Eoc Ei sets the final potential in absolute vs Ref the reference electrode potential or versus the previous open circuit potential or previous the initial potential Curtail step duration if I lt 4 pA A fixes a minimum value for the current AS soon as the measured current value is lower than l the next potential step is performed This is the galvanostatic acceleration Record AQ every
250. vano Galvanodynamic detailed diagram Scan with di dt mA s with pA A Ss defines the scan rate The same as for the Modular Potentio technique entering the dl dt value will automatically calculate the dl and dt values in order to minimize the current steps dl Nevertheless one can enter dl and dt directly from I pA A vs lt None gt Ictrl Imeas to pA A vs lt None gt Ii defines the initial l and final current of the scan Limit Ewe to E V and AQ to AQy fA h A h pC KC 67 Techniques and Applications Manual defines the potential and sequence charge limits The E limit is dependent on the charge sign the limit is Ewe gt Ex if l gt 0 Ewe lt E else To cancel the limits type p for pass in the E edition box and zero for AQwy For the galvanostatic mode AQy is not accessible and is calculated from and ts AQm ls ts Record every dE mV dt s and dQ fA h A h pC kC defines the recording conditions A zero value cancels the corresponding recording criterion These values can be entered simultaneously If so the first condition that is reached determines the recording For the galvanostatic mode dQ is not accessible and is calculated from ls and dt dQ ls dtp enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users man
251. xecuted 2 times nN 0 disables the loop and the execution continue to the next line Ns Ns 1 If there is no next line the execution stops Here it is possible to loop to the first instruction N 0 and the current instruction Ng N 3 2 5 Constant Current CstC The constant current CstC technique is specially dedicated to fuel cell s or photovoltaic cell s testing It is designed to apply successively several current steps to the cell s Between each current step an open circuit voltage period can be added 129 Techniques and Applications Manual Rest for tp Limit dE yye dt lt dER fdt Record ever dER or dtp Apple Is for t Limits Eye gt Ep AQI gt AUM Record every dE or dt E Range Range Bandwidth Go back to sequence Ng for My lt o ho mogo Bo mwh oo mV o1 8 00 000 ma s lt None gt i hf ma jooo 8 pass Y i BEF rd Ewe 0 0 rev 0 01 oo 3 ov 54 Senay Fay 100 m 5 medium ka kal 0 SESS anoke Aachen m time s ATAV NARAN Fig 117 Constant Current detailed diagram e Rest period The rest period is an open circuit voltage period Refer to the OCV description for more details e Current step Apply l pA A vs lt none gt Ictrl Imeas the current step is set to a fixed value or relatively to the previous controlled current le that is the current of the previous sequence cur
252. y described See section 2 4 page 64 The WAIT and LOOP options have been designed especially for linked experiments Building linked experiments is very easy with the right click menu When the user right clicks on the parameter settings window the following menu appears 72 New Ctrl N del Load Settings Ctrl L Import Settings From Text fe Load Data File Ctrl O 5 Load Report Save Settings As Ctrl 5 save As Custom Application Import From Text Export as Text Ctrl T 2 Accept Ctrl M ge Cancel Modify b Run Ctrl R Pause Next Technique Print Ctrl P Exit Fig 171 Mouse right click with the insert and remove options The second frame is especially dedicated to linked experiments The Insert New Technique function opens the technique selection window and offers the ability to insert a new technique into the experiment The user can select where he wants to add the new technique into the settings according to the activated selected technique green frame around the technique name in the parameter settings window at the bottom left corner frame of the technique selection window Insert Technique C Before f After 194 4 2 Techniques and Applications Manual Fig 172 Insert before after option of the technique selection window If the technique is not in the correct position in the experiment the user can easily move it up or down using the Move Technique Before and Move Techniqu
253. ype p for pass in the E edition box and zero for AQwy For the galvanostatic mode AQ is not accessible and is calculated from and ts AQm I ts Record every dE mV dt s and dQ fA h A h pC kC defines the recording conditions A zero value cancels the corresponding recording criterion These values can be entered simultaneously If so the first condition that is reached determines the recording For the galvanostatic mode dQ is not accessible and is calculated from and dt dQ ls dtp 66 Techniques and Applications Manual enables the user to select the potential range for adjusting the potential resolution with his system See EC Lab software users manual for more details on the potential resolution adjustment With I Range and Bandwidth fixes the current range and bandwidth for this experiment 2 4 1 3 Galvanodynamic Mode 2 OY 0 Hode Galyvanostatic 1 Galvanodynarmic 2 Scant with difdt f 000000000 mAs with o 200 pA per 0002 3 from li 50 000 Ay ve lt None gt tole hooo WA WE lt None gt gt Limits Ep 0 500 if IAG gt AQw 0 000 mAh gt Record every dE i D m dtp 0 500 0 3 dap 0000 m amp h E Range 25W 25Y i Arena Fay Range 100 p Bandwidth R medium Go back to sequence Ng p RGIS aos feces for mge E tires Avie vase SARA Fig 57 Modular Gal

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