In my knowledge, the most common redox couple used for ECSA determination is the ferri/ferrocyanide ([Fe(CN)6]3−/[Fe(CN)6]4−) couple in a potassium chloride (KCl) supporting electrolyte solution. This redox pair has well-defined oxidation and reduction peaks, which makes it suitable for accurately measuring the double-layer capacitance of the electrode. So, I want to know if any other electrolyte can be used for this purpose?