Conductance of concentrated electrolytes: multivalency and the Wien effect

TL;DR

This paper extends a stochastic density-functional theory model to multivalent electrolytes and high electric fields, accurately predicting conductivity behavior and the Wien effect at high concentrations.

Contribution

It introduces a generalized model for electrolyte conductance that accounts for multivalency and strong electric fields, expanding prior low-field, monovalent-focused theories.

Findings

Model agrees well with experimental data

Captures the Wien effect at high electric fields

Extends understanding of electrolyte conductance at high concentrations

Abstract

The electric conductivity of ionic solutions is well understood at low ionic concentrations of up to a few millimolar but becomes difficult to unravel at higher concentrations that are still common in nature and technological applications. A model for the conductivity at high concentrations was recently put forth for monovalent electrolytes at low electric fields. The model relies on applying a stochastic density-functional theory and using a modified electrostatic pair-potential that suppresses unphysical, short-range electrostatic interactions. Here, we extend the theory to multivalent ions as well as to high electric fields where a deviation from Ohm's law known as the Wien effect occurs. Our results are in good agreement with experiments and recent simulations.