Analysis of potentiostatic current transients at metal/liquid interfaces: resolving the effects of a finite step interval

Potentiostatic current transients are used routinely for electrochemical analysis of metal/liquid interfaces. These measurements can be affected by both the electrochemical cell and the potentiostat used for such experiments. We demonstrate this in the present report with double‐layer charging experiments using a gold electrode in aqueous electrolytes of NaF and NaNO 3 . By employing a high‐resolution potentiostat, we show that the apparently instantaneous voltage step actually has a finite temporal width. The double‐layer charging current develops an additional feature due to this behavior of the voltage step. We present a theoretical framework to resolve these instrumental effects from the actual electrical response of the double layer. The results are compared with a set of independent measurements of the same quantities using impedance spectroscopy.