General equivalent circuits for faradaic electrode processes under electrochemical reaction control

Several different types of equivalent circuits for the faradaic electrode process involving n state variables besides electrode potential are established in terms of the corresponding faradaic admittance equation in the case of ignoring mass transport. These circuits can develop into general equivalent circuits by introducing negative resistive and inductive and capacitive elements, each of which can be used to analyze any electrochemical impedance spectroscopy of the faradaic electrode process under electrochemical reaction control. The correspondence between element values of the circuits and electrochemical parameters of the faradaic admittance equation has also been determined by comparing the admittance or impedance of the equivalent circuit and the faradaic admittance or impedance equation. The use of general equivalent circuits; together with the faradaic admittance equation, greatly simplifies the analysis of electrochemical impedance spectroscopy for the faradaic electrode processes. (C) 1999 The Electrochemical Society. S0013-4651(98)05-055-1. All rights reserved.