Hello Karlo Martinez ,

I hope you are doing well.

Your Nyquist plot is not a semi circle but how does it look like?

You may want to check the quality of the connections (cable, clips...) if everything looks fine you should try polishing the electrode's connections as well.

Regarding the condition of the reference electrode, you may want to check the saturation of the solution inside and sometimes you even need to unclog the frit.

As far as the impedance measurements are concerned, you may want to check the cell resistance, maybe expand the frequency range (starting at higher frequency 10 kHz for example) in order to see a semi-circle.

I do not know how you are modifying your working electrodes, is it a porous material? The type of material could affect the diffusion (at lower frequencies).

Here is a link for more information on overloads :

https://www.gamry.com/support/technical-support/getting-started-with-gamry-software/basic-explanation-of-overloads/

Best regards,

Marie

Hello Karlo Martinez ,

Further to Marie Berthuel 's good suggestions, you may also want to see if your potentiostat has the ability to adjust the bandwidth factor.

See the attached application note. Figure 8 shows the relationship between current range and capacitance on cell stability.

At the end of the document there are also some general suggestions:

@Marie Berthuel and @Jules Lloyd Hammond Thanks for the suggestions, the plot forms kind of a zig zag. I found the reason was there a bubble of air formed near the membrane of the reference. But if I ever run into the issue again, I'll be better informed

Dear Karlo Martinez

Bad contact in the reference electrode circuit is, in my view, the most common cause of overload conditions. Until beginning potentiostat power, make sure the open-circuit potential is stable.