A theory of inductive loops in electrochemical impedance spectroscopy

TL;DR

This paper presents a theoretical analysis of inductive loops in electrochemical impedance spectroscopy, showing how time-invariance failure causes low-frequency inductive behavior and providing a new integral impedance model.

Contribution

It introduces an asymptotic analysis and a novel integral representation of impedance that captures inductive loops caused by non-time-invariant properties.

Findings

Inductive loops arise from time-invariance failure in electrochemical systems.

The new impedance model reduces to standard form at high frequencies.

The model accurately predicts low-frequency inductive behavior.

Abstract

We demonstrate that failure of time-invariance assumption in the modeling of electrochemical systems by equivalent circuits can lead to the formation of low frequency "inductive loops" that manifest themselves as positive imaginary parts of the impedance function. Assuming that the properties of the equivalent circuits change slowly in time we perform an asymptotic analysis and obtain a new integral representation of the impedance function that reduces to the standard one at high frequencies, while exhibiting inductive loops at low frequencies.