Non-linear response of an electrode-electrolyte interface impedance with the frequency

Abstract

In this paper we analyze the frequency response of a distributed parameters non-linear circuit. This circuit is a fractal model of an electrode-electrolyte interface. The results show that the series equivalent resistance Req decreases as the number of fractal levels rises. Its frequency behavior is similar to the results described by other authors that used a constant phase angle element. At low frequency range, the series equivalent reactance Xeq decreases with frequency and Req shows a flat response in this range. The model also explains how interface geometry modifies the values of some electrochemical parameters. As roughness increases the Argand diagram shows smaller semicircles. The model behavior is like a single dispersion system with its central frequency increasing with the electrode roughness.