What is the proper way to measure the capacitance of the double layer for a stainless steel in a low-conductivity electrolyte?
In this electrolyte the stainless steel is in passive state, I am interested in the capacitance at the rest potential (open circuit potential)?
As far as I understand it can be determined from the electrochemical impedance, but in such case I guess I need an electrical circuit equivalent.
Is there any other procedure besides impedance?