Can anybody comment on any differences that might occur when EIS measurements are carried out on two-electrode cells versus three-electrode cells? I have seen papers report EIS data using both types of cells.
Hi Sankalp.
Your question is general, since you didn't mention the identity of your electrdoes, so I will try to give an answer- hope it helps.
When you are using Ref electrode and taking EIS, all the voltage in the AC you use is falling on your Working electrode. Because the RE is non-polarizable with low impedance.
However, when using 2 electrodes, this isn't necessarily the case. If your counter is polarizable, or with similar polarizability to the WE the signal you will get is a composition of response from both electrodes.
Thank you for your help Dr.Noked. I am trying to see how my electrode material performs at much higher frequencies (e.g. capacitace, phase vs. frequency). I am testing in an aqueous electrolyte using activated carbon as my counter electrode and Ag/AgCl is my reference . I know activated carbon will likely be much less polarizable than my working electrode above a few Hz. From your answer, it seems to me that a symmetric two-electrode cell is ideal for probing high frequency performance compared to my current setup or a two-electrode asymmetric cell with overcapacitive counter. Please correct me if I am wrong.
Functionalized Graphene as a Catalytic Counter Electrode in Dye-Sensitized Solar Cells
http://www.princeton.edu/~cml/assets/pdf/pu_10_xxroy-mayhew.pdf
You can get some experimental information in this reference.
A reference electrode is used to determine the potential across the electrochemical interface accurately for Electrochemical Impedance Spectroscopy (EIS) experiment.A two-electrode system for the cell is used to control of the potential across the electrochemical interface between working electrode and count electrode.
In EIS the voltage amplitude can be several orders of magnitude smaller than the magnitude of the applied voltage, it seems to me that a three-electrode cell with symmetric working and counter electrodes would always be superior to a two-electrode setup for EIS in my case. Is this reasonable to say?
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