A number of people thanked me for explaining how to connect a Keithley potentiostat to a 3 electrode cell. Some of our customers who are doing galvanic cell (battery) testing do not use a reference electrode. They need to know how to hook up to a cell for charge / discharge applications.
Connections are simple for a galvanic cell:
- FORCE HI to the positive terminal
- SENSE HI to the positive terminal
- FORCE LO to the negative terminal
- SENSE LO to the negative terminal
The potentiostat can be programmed for negative current to discharge the cell. The instrument is then operating in what we call “sink” mode; it is sinking power from the cell. The instrument can then be programmed for positive current to charge the cell (assuming it is a secondary, re-chargeable type). I recommend that you use the Square Wave method (built in script) for charge / discharge operation.
The instruments can also do constant current charge / discharge, constant voltage charge, and with internal scripts they can handle switching from constant current (CC) to constant voltage (CV) charge as needed by Lithium-ion cells.
Read more on the Keithley 2450-EC and the 2460-EC potentiostats.
Bill Pelster is the Director of Quality for the Keithley product line of Tektronix, Inc. He has been with the company for 37 years and has worked in engineering, applications, service, product safety, and quality. He has developed application software for testing high temperature superconductors and is now a member of the Keithley eChem team. Bill holds a BEE degree from Cleveland State University (Fenn College) and an MBA from CWRU (Weatherhead School).