Immittance response of an electrolytic cell in the presence of adsorption, generation, and recombination of ions

TL;DR

This paper theoretically investigates how adsorption, generation, and recombination of ions affect the electrical response of electrolytic cells using a continuum model, providing exact admittance expressions.

Contribution

It introduces a comprehensive theoretical analysis of the electrolytic cell's response considering ion dynamics, adsorption, and recombination within the Poisson-Nernst-Planck framework, including exact admittance formulas.

Findings

Derived a general exact admittance expression for the system.

Analyzed effects of ion mobility differences on response.

Provided insights into the electrochemical behavior under various conditions.

Abstract

Effects of the adsorption-desorption process on the immittance response of an electrolytic cell are theoretically investigated in the framework of the diffusional Poisson-Nernst-Planck (PNP) continuum model, when the generation and recombination of ions is taken into account. The analysis is carried out by searching solutions for the drift-diffusion equation coupled to the Poisson's equation relating the effective electric field to the net charge density. The effect of different ion mobilities on the immittance, i.e., situations with equal and different diffusion coefficients for positive and negative ions, are considered. A general exact expression for the admittance in the context of the linear approximation is obtained.