A comparison of the Nernst-Planck and Maxwell-Stefan approaches to modelling multicomponent charge transport in electrolyte solutions

Abstract

An understanding of charge transport in electrolytic solutions is of vital importance in the modelling and simulation of electrochemically and photoelectrochemically active porous media. To this end, we present two multicomponent charge transport models for an electrolyte system based on the generalized Maxwell-Stefan equations and the dilute solution Nernst-Planck equations. These transport models are used to develop two further models of a simple electrochemical cell consisting of ideally polarizable metal electrodes and a binary electrolyte. The results from the numerical solution of these Maxwell-Stefan and Nernst-Planck models are compared for a range of electrolyte concentrations and the applicability of each model approach is discussed.