Non-linear response of electrode–electrolyte interface at high current density

A distributed parameter non-linear circuit is presented as fractal model of an electrode–electrolyte interface. It includes the charge transfer resistance and the double layer capacitance at each fractal level. The circuit explains the linear behavior of its series equivalent resistance Req with signals of amplitudes <20 mV and constant frequency; however, for amplitudes beyond that limit, non-linearitiy is manifested in the dc component of the Req Fourier spectrum. As a consequence, both the equivalent resistance and reactance drop with voltage, facts reported experimentally by other authors.