Resistance-induced peaks in cyclic voltammograms of systems that can be switched electrochemically between an insulating and conductive state

Abstract

In the cyclic voltammetry of certain films that exhibit in general a reversible or quasi-reversible behavior, prepeaks associated with the main oxidation peak may be found under certain conditions. In the present paper we demonstrate that this phenomenon can be explained by consideration of resistive effects in the film. A simple model presumes that the electrochemistry is reversible and that the film resistivity ( R o) is inversely related to the amount of (oxidizing) charge ( q t) by a simple power relationship: ( R o) = a( q max/ q t) P . The shape of the theoretical cyclic voltammogram is a function of a, P, and the scan rate, and it mimics qualitatively many of the experimentally observed features, including prepeaks and shoulders.