Dynamics of Ion Transport in Ionic Liquids

TL;DR

This paper develops a continuum model for ion transport in ionic liquids by coarse graining a lattice exclusion process, revealing unique charging behaviors consistent with experimental observations.

Contribution

It introduces a novel continuum framework linking microscopic particle dynamics to macroscopic ion transport in ionic liquids.

Findings

The model predicts a vanishing mobility matrix at high densities.

The charging behavior differs from traditional electrolytes.

Qualitative agreement with experimental and simulation data.

Abstract

A gap in understanding the link between continuum theories of ion transport in ionic liquids and the underlying microscopic dynamics has hindered the development of frameworks for transport phenomena in these concentrated electrolytes. Here, we construct a continuum theory for ion transport in ionic liquids by coarse graining a simple exclusion process of interacting particles on a lattice. The resulting dynamical equations can be written as a gradient flow with a mobility matrix that vanishes at high densities. This form of the mobility matrix gives rise to a charging behaviour that is different to the one known for electrolytic solutions, but which agrees qualitatively with the phenomenology observed in experiments and simulations.