background image

Section 2: Cyclic Voltammetry 

Models 2450-EC, 2460-EC, and 2461-EC Potentiostats And Galvanostats User's Manual 

 

2-2 

077110402/November 2016 

 

Test application parameters 

You must enter test parameters that are consistent with the following values. Otherwise, you may 
receive unsettled and inaccurate measurements. 

The Cyclic Voltammetry test application parameters are listed below. 

Model 2450-EC 

 

Potential range: -

20 V ≤ E ≤ +20 V 

 

Cu

rrent measure ranges: 10 μA, 100 μA, 1 mA, 10 mA, 100 mA, 1 A 

 

Source limit (compliance): 100 % of selected current range 

 

Scan rate: 0.1 mV per second to 3500 mV per second 

 

Potential step size during scanning: 

 

100 μV (0.1 mV per second ≤ scan rate < 35 mV per second) 

 

1 mV (35 mV per second ≤ scan rate < 350 mV per second ) 

 

10 mV (350 mV per second ≤ scan rate ≤ 3500 mV per second) 

 

Number of cycles: 1 to 100 

 

User-selectable sampling intervals: 

 

Points per test (10 to 10,000) 

 

Points per cycle (10 to 10,000) 

 

Seconds per point (.01 to 100) 

 

Points per second (.01 to 100) 

 

Maximum total number of samples: 100,000 

Models 2460-EC and 2461-EC 

 

Potential range: -

20 V ≤ E ≤ +20 V 

 

Current measure ranges: 1 mA, 10 mA, 100 mA, 1 A, 4 A, 5 A, 7 A 

 

Source limit (compliance): 100 % of selected current range 

 

Scan rate: 0.1 mV per second to 3500 mV per second 

 

Potential step size during scanning: 

 

100 μV (0.1 mV per second ≤ scan rate < 35 mV per second) 

 

1 mV (35 mV per second ≤ scan rate < 350 mV per second ) 

 

10 mV (350 mV per second 

≤ scan rate ≤ 3500 mV per second) 

 

Number of cycles: 1 to 100 

 

User-selectable sampling intervals: 

 

Points per test (10 to 10000) 

 

Points per cycle (10 to 10000) 

 

Seconds per point (.01 to 100) 

 

Points per second (.01 to 100) 

 

Maximum total number of samples: 100,000 

 

Summary of Contents for KEITHLEY 2450-EC

Page 1: ...User s Manual 077110402 November 2016 P077110402 077110402 Models 2450 EC 2460 EC and 2461 EC Potentiostats and Galvanostats A Greater Measure of Confidence www tek com keithley...

Page 2: ...Keithley Instruments Other brand names are trademarks or registered trademarks of their respective holders The Lua 5 0 software and associated documentation files are copyright 1994 2015 Lua org PUC R...

Page 3: ...s may be connected to mains These instruments will be marked as category II or higher Unless explicitly allowed in the specifications operating manual and instrument labels do not connect any instrume...

Page 4: ...ead the associated information very carefully before performing the indicated procedure The CAUTION heading in the user documentation explains hazards that could damage the instrument Such damage may...

Page 5: ...e 2 8 Save or load the test parameter data 2 10 Run the test and view the graph 2 12 Acquire the open circuit potential Eoc 2 13 Save the test data to the flash drive 2 14 View the results saved to th...

Page 6: ...ew the results saved to the flash drive 5 12 View the Reading Table or measurement Statistics 5 12 View the Event Log 5 13 End the test application 5 13 Chronoamperometry 6 1 Chronoamperometry 6 1 Tes...

Page 7: ...ction of time Potential Pulse and Square Wave with Current Measure Sources potential at programmable peak and base levels The resulting current at the pulse peak level is recorded Current Pulse and Sq...

Page 8: ...U key then select Info Manage under System The firmware version is at the upper left of your display The latest firmware is available from the Keithley Instruments website http www tek com keithley Th...

Page 9: ...he prompt to reboot select Yes Select the high impedance output off state Before making physical connections from the instrument to the test cell set the output of the instrument to the high impedance...

Page 10: ...can run the test applications from the flash drive or copy the files from the flash drive to the instrument If you choose to copy the applications you must also copy the support files EC_Framework tsp...

Page 11: ...Figure 3 Copying the file to the instrument Cable assembly details The cable is an electrically shielded 1 m 39 37 in assembly with stackable safety banana plugs on both ends This cable simplifies the...

Page 12: ...use the supplied cable to connect your electrochemical cell to these jacks The SENSE terminals are used to measure voltage at the device under test DUT When you use sense leads the voltage drop across...

Page 13: ...he working electrode of your electrochemical cell and connect the CE and RE pair to the counter electrode of the cell Figure 7 Two electrode cell testing cable connections For three electrode applicat...

Page 14: ...fe secure way to connect to your device Figure 10 Alligator clip attached to accessory cable connector For small cells and electrodes you can use commercially available banana to microclip connectors...

Page 15: ...and Menu screens in standard mode When you run an electrochemistry test application the default Home and Menu screens are replaced by application specific Home and Menu screens These screens vary dep...

Page 16: ...ltammetry test application has adjustable parameter settings and enables real time graphing of a voltammogram on the display of the SMU potentiostat without using a computer Test parameters are input...

Page 17: ...per second 10 mV 350 mV per second scan rate 3500 mV per second Number of cycles 1 to 100 User selectable sampling intervals Points per test 10 to 10 000 Points per cycle 10 to 10 000 Seconds per poi...

Page 18: ...pt Figure 13 Active script indicator 3 Select the preloaded Cyclic Voltammetry test script potentiostats and galvanostats only or connect the supplied USB drive to your SMU instrument to locate the in...

Page 19: ...ze Start Test Select this control to immediately begin the test This option becomes Stop Test when the test runs Save Data Select this control to save the test data to a csv file on a flash drive This...

Page 20: ...wn in the next figure You can select up to four voltage potential vertices which are defined as E1 or E initial E2 E3 and E4 in the next figure The slope of the lines is determined by the the scan rat...

Page 21: ...vertices Figure 19 Scan Settings menu defining four vertices 5 Enter each vertex value in the range of 20 V After you define the vertices select the potential reference Eref or Eoc If you select Eref...

Page 22: ...ring the experiment You can select a scan rate of 0 1 mV per second to 3500 mV per second To select the Scan Rate 1 From the Scan Settings menu select Scan Rate Figure 21 Scan Settings menu selecting...

Page 23: ...active buffer of the instrument cvBuffer The buffer can hold a maximum of 100 000 readings The following table describes the available interval units and accompanying range of values Sampling rate uni...

Page 24: ...t measurement range 1 From the Measure Settings screen select Current Range Figure 25 Measure Settings menu selecting the Current Range When the test runs your potentiostat will limit the magnitude of...

Page 25: ...five test parameter configurations can be stored To save the test parameters 1 From the Menu screen select Save Settings If you have saved a settings file previously with the same File Selection numbe...

Page 26: ...instrument model on which they were created and saved For example you cannot load test parameter settings created with a 2450 EC to a 2460 EC 1 From the Menu screen select Load Settings Figure 29 Sel...

Page 27: ...port of the potentiostat by simultaneously pressing the HOME key and the ENTER key The file name has the format imgmmdd_xxxxxx png where mmdd represents the instrument month and day and xxxxxx is a sy...

Page 28: ...pted by the test application as shown in the next figure Figure 32 Prompt for Eoc measurement If you select Yes the instrument measures the open circuit potential Eoc of your electrochemical cell If y...

Page 29: ...ve the test data to the flash drive 1 Make sure your flash drive is inserted into the front panel USB port 2 From the test application home screen select Save Data 3 Specify a file name then select OK...

Page 30: ...these events You can also specify which events are shown in the event log which ones are logged and which ones generate popup messages Figure 36 Viewing the Event Log See your Keithley Instruments 245...

Page 31: ...ith respect to the reference electrode The resulting current i flowing to the working electrode is measured with the ammeter AM This process is usually repeated for a range of E An example procedure t...

Page 32: ...n reverses again and the voltage is swept until it reaches E4 From the potential sweep important information about the experiment can be derived and analyzed Keithley galvanostat scan theory The 2450...

Page 33: ...a fixed point t for each discrete voltage step which may not be at the same time for each step See the following figure Figure 40 Voltage step measurements Conversely the 2450 EC 2460 EC and 2461 EC u...

Page 34: ...pplied to the cell This voltage measurement is made using the galvanostat to source current and measure voltage see the next figure The instrument sources 0 A on the 1e 6 range using a 4 wire configur...

Page 35: ...igured for 4 wire measurements as shown in the next figure In this setup the instrument is configured to source 0 A and measure voltage If you measure the OCP before performing any test you do not hav...

Page 36: ...C and 2461 EC Potential measure ranges 200 mV 2 V 7 V 10 V 20 V Sample interval 0 75 s sample interval 100 s Number of samples 1 to 100 000 Run the Open Circuit Potential test application To run the t...

Page 37: ...data This is useful for constraining all of the data to the screen s viewing size Start Test Select this control to immediately begin the test This option becomes Stop Test when the test runs Save Da...

Page 38: ...the Potential Range 1 Press the MENU key then select Measure Settings 2 Select Potential Range Figure 48 Measure Settings menu selecting Potential Range 3 Choose a value Note that the choices are dif...

Page 39: ...fy the sample interval time in seconds per point The sample interval time is illustrated in the next figure You can choose an interval from 0 75 to 100 seconds per point Figure 51 Sample Interval time...

Page 40: ...ve test parameter configurations can be stored To save the test parameters 1 From the Menu screen select Save Settings Note that your Menu screen options are different depending on the test you are ru...

Page 41: ...You are notified when the load completes 4 Select OK to clear the prompt Run the test and view the graph To start the experiment and view the graph or data 1 Press the HOME key 2 Select Start Test Th...

Page 42: ...to select Stop Test before selecting End App Stop Test turns off the instrument s output Hazardous voltages may be present on all output and guard terminals To prevent electrical shock that could caus...

Page 43: ...program on a computer Current voltage time and general parameters for the test are included in the file View the Reading Table or measurement Statistics When the test completes you can view the indiv...

Page 44: ...w these events You can also specify which events are shown in the event log which ones are logged and which ones generate popup messages Figure 60 Viewing the Event Log See your Keithley Instruments 2...

Page 45: ...e Various parameters of the pulse wave are displayed in the figure below Though not pictured there is also a brief latency period between the end of the measurement and the end of the pulse to allow t...

Page 46: ...3600 s 100 ms pulse width 0 99 period Current measure range 1 A 4 ms period 3600 s 2 ms pulse width 0 99 period Sample time Minimum is 166 667 s Maximum is lesser of 166 667 ms and pulse width 1 ms N...

Page 47: ...or 3 Select the preloaded Potential Pulse and Square Wave test script potentiostats and galvanostats only or connect the supplied USB drive to your SMU instrument to locate the included Potential Puls...

Page 48: ...est data to a csv file on a flash drive This option is only visible after the test runs Cursor Select this control to cycle through the available cursor placements None Vertical Horizontal and Both Re...

Page 49: ...Enter a value Figure 67 Entering a Base Potential 3 Select OK Next you will adjust the Peak Potential This setting allows you to adjust the maximum potential that the instrument will attempt to force...

Page 50: ...our expected maximum current Setting the current range also sets a current limit which can be used to stop the test or otherwise protect your DUT Your potentiostat will limit the current to 105 percen...

Page 51: ...se Width 3 Select OK The Sample Time is the length of time over which the actual measurement is taken The Sample Time cannot exceed the Pulse Width minus 1 ms PW 1 ms The measurement is taken at the e...

Page 52: ...le the Number of Cycles the Program Time is disabled Conversely if you enable the Program Time the Number of Cycles condition is disabled The Source Limit setting is independent of the other two setti...

Page 53: ...the waveform if the current level reaches the programmed source or compliance limit The source limit is set to 105 percent of the selected current measure range To enable the Source Limit end conditi...

Page 54: ...saved test parameters Test parameters can only be loaded to the same instrument model on which they were created and saved For example you cannot load test parameter settings created with a 2450 EC to...

Page 55: ...o the USB port of the potentiostat by simultaneously pressing the HOME key and the ENTER key The file name has the format imgmmdd_xxxxxx png where mmdd represents the instrument month and day and xxxx...

Page 56: ...e flash drive 1 Make sure your flash drive is inserted into the front panel USB port 2 From the test application home screen select Save Data 3 Specify a file name then select OK 4 Select OK on the co...

Page 57: ...ed by your instrument Through the Event Log menu you can view these events You can also specify which events are shown in the event log which ones are logged and which ones generate popup messages Fig...

Page 58: ...rious parameters of the pulse wave are displayed in the figure below Though not pictured there is also a brief latency period between the end of the measurement and the end of the pulse to allow the i...

Page 59: ...00 ms period 3600 s 100 ms pulse width 0 99 period Ipeak or Ibase 1 05 A 4 ms period 3600 s 2 ms pulse width 0 99 period Sample time Minimum is 166 667 s Maximum is lesser of 166 667 ms and pulse widt...

Page 60: ...ndicator 3 Select the preloaded Current Pulse and Square Wave test script potentiostats and galvanostats only or connect the supplied USB drive to your SMU instrument to locate the included Current Pu...

Page 61: ...e the test data to a csv file on a flash drive This option is only visible after the test runs Cursor Select this control to cycle through the available cursor placements None Vertical Horizontal and...

Page 62: ...Enter a value Figure 89 Entering the Base Current 3 Select OK To adjust the Peak Current 1 From the Pulse Settings screen select Peak Current 2 Enter a value Figure 90 Entering the Peak Current 3 Sel...

Page 63: ...ercent of the selected range Now you will adjust the Period This setting lets you specify the duration of one cycle of the pulse wave The Period and Pulse Width settings are related You cannot set the...

Page 64: ...end of the pulse A brief latency period between the end of the measurement and the end of the pulse allows the analog to digital converter in your galvanostat to complete the measurement To adjust the...

Page 65: ...t On 4 Select the Number of Cycles Value control 5 Enter a value then select OK Use the Program Time end condition to stop generating the waveform after a specified time interval The pulse wave stops...

Page 66: ...test parameter configurations can be stored To save the test parameters 1 From the Menu screen select Save Settings Note that your Menu screen options are different depending on the test you are runn...

Page 67: ...You will be notified when the load completes 4 Select OK to clear the prompt Run the test and view the graph To run the test and view the graph 1 Press the HOME key 2 Select Start Test The output tur...

Page 68: ...select Stop Test before selecting End App Stop Test turns off the instrument s output Hazardous voltages may be present on all output and guard terminals To prevent electrical shock that could cause...

Page 69: ...rogram on a computer Current voltage time and general parameters for the test are included in the file View the Reading Table or measurement Statistics When the test completes you can view the individ...

Page 70: ...these events You can also specify which events are shown in the event log which ones are logged and which ones generate popup messages Figure 103 Viewing the Event Log See your Keithley Instruments 24...

Page 71: ...U potentiostat can repeat this process for up to ten defined steps Key timing parameters are shown in the figure below Note that there is always a measurement at the beginning of each step Figure 104...

Page 72: ...mum is 166 667 s Maximum is lesser of 166 667 ms and sample interval 5 ms and step duration 5 ms Maximum number of samples 100 000 total for all steps Models 2460 EC and 2461 EC Step potential 20 V Es...

Page 73: ...ns to run immediately and the following screen is displayed Figure 107 Chronoamperometry test home screen The test home screen controls include End App Select this control to immediately stop the test...

Page 74: ...the Menu screen depending on the application The following graphic shows the Chronoamperometry main Menu You will learn the function for each option later in this section Figure 108 Chronoamperometry...

Page 75: ...e MENU key then select Step Settings 2 Select Number of Steps 3 Enter a value then select OK The next figure shows three steps defined Figure 110 Step Settings menu Next you must define the Potential...

Page 76: ...device under test DUT Make sure to choose a range higher than your expected maximum current Setting the current range also sets a current limit which can be used to stop the test or otherwise protect...

Page 77: ...Save or load the test parameter data You can save your test parameters to the front panel flash drive at any time Up to five test parameter configurations can be stored To save the test parameters 1...

Page 78: ...saved test parameters Test parameters can only be loaded to the same instrument model on which they were created and saved For example you cannot load test parameter settings created with a 2450 EC to...

Page 79: ...USB port of the potentiostat by simultaneously pressing the HOME key and the ENTER key The file name has the format imgmmdd_xxxxxx png where mmdd represents the instrument month and day and xxxxxx is...

Page 80: ...flash drive 1 Make sure your flash drive is inserted into the front panel USB port 2 From the test application home screen select Save Data 3 Specify a file name then select OK 4 Select OK on the con...

Page 81: ...ed by your instrument Through the Event Log menu you can view these events You can also specify which events are shown in the event log which ones are logged and which ones generate popup messages Fig...

Page 82: ...lvanostat can repeat this process for up to ten defined steps Key timing parameters are displayed in the figure below Note that there is always a measurement at the beginning of each step Figure 123 P...

Page 83: ...um is 166 667 s Maximum is lesser of 166 667ms and sample interval 5 ms and step duration 5 ms Maximum number of samples 100 000 total for all steps Models 2460 EC and 2461 EC Step current 7 35 A Iste...

Page 84: ...on begins to run immediately and the following screen is displayed Figure 126 Chronopotentiometry test home screen The test home screen controls include End App Select this control to immediately stop...

Page 85: ...ill learn the function for each option later in this section Figure 127 Chronopotentiometry main Menu Configure the Step and Measure Settings Select Step Settings to specify the number level and durat...

Page 86: ...The next figure shows three steps defined Figure 130 Step Settings menu Next you must define the Current and Duration for each step To define the Current and Duration 1 From the Measure Settings menu...

Page 87: ...ross the device under test DUT Make sure to choose a range higher than your expected maximum potential Setting the Potential Range also sets a potential limit which can be used to stop the test or oth...

Page 88: ...e Save or load the test parameter data You can save your test parameters to the front panel flash drive at any time Up to five test parameter configurations can be stored To save the test parameters 1...

Page 89: ...saved test parameters Test parameters can only be loaded to the same instrument model on which they were created and saved For example you cannot load test parameter settings created with a 2450 EC t...

Page 90: ...nostat by simultaneously pressing the HOME key and the ENTER key The file name has the format imgmmdd_xxxxxx png where mmdd represents the instrument month and day and xxxxxx is a system generated num...

Page 91: ...e flash drive 1 Make sure your flash drive is inserted into the front panel USB port 2 From the test application home screen select Save Data 3 Specify a file name then select OK 4 Select OK on the co...

Page 92: ...ted by your instrument Through the Event Log menu you can view these events You can also specify which events are shown in the event log which ones are logged and which ones generate popup messages Fi...

Page 93: ...operty of Keithley Instruments All other trademarks and trade names are the property of their respective companies Keithley Instruments Corporate Headquarters 28775 Aurora Road Cleveland Ohio 44139 44...

Reviews: