Determination of Electrode Kinetics Parameters from Dynamic Electrochemical Impedance Spectroscopy Measurements via Potential-Program Invariant Functions

Abstract

Dynamic electrochemical impedance spectroscopy, dEIS, comprises repetitive impedance spectrum measurements while slow scan-rate voltammetry is running. Its main virtue is the short measurement time, reducing the danger of contamination of the electrode surface. To further the use of dEIS, we have recently elaborated a set of theories aimed at the related data processing for three groups of fundamental electrode reactions: diffusion-affected charge transfer, charge transfer of surface-bound species, and adsorption−desorption. These theories yielded equations by which the voltammograms can be transformed to potential-program invariant forms, allowing an easy calculation of the rate coefficients; similar equations have been derived for the potential dependence of equivalent circuit parameters obtained from the impedance spectra. In this Perspective, the above derivations are condensed into a single, unified one. The theory is recommended to evaluate electrode kinetic measurements, particularly when the potential dependence of rate coefficients is under study.