Potentiodynamic electrochemical impedance spectroscopy

Abstract

Potentiodynamic electrochemical impedance spectroscopy (PDEIS) is a technique for simultaneous ac and dc electrochemical response investigation on the potential scale. Analogous to the potentiodynamic voltammetry, PDEIS gives the variation of the dc current and, additionally, the variation of impedance spectra in the same potential scan. Thus, a comprehensive dc and ac response is acquired in a simple experiment similar to the acquisition of a common cyclic voltammogram. This is provided by the virtual instruments that also analyse the response in terms of equivalent electric circuits, giving at the output the dependence on the potential of several key parameters of electrochemical interface. The new technique simplifies considerably the investigation of stationary electrochemical systems and provides the unique possibility for the comprehensive electrochemical characterisation of unstable systems and transient states. A lot of examples is presented in the review to illustrate these new possibilities.