Linking dynamics and structure in highly asymmetric ionic liquids

TL;DR

This paper presents a theoretical model linking the structure and dynamics of asymmetric ionic liquids, revealing novel glassy states where one ion species is arrested while the other remains mobile, aiding the design of single-ion conductors.

Contribution

It introduces a primitive model and applies SCGLE theory to connect ion size ratios with mobility, uncovering new glassy states in asymmetric ionic liquids.

Findings

Identification of glassy states with arrested or mobile ions

Correlation between ion size ratio and mobility

Potential for developing single-ion conducting materials

Abstract

We explore an idealized theoretical model for the transport of ions within highly asymmetric ionic liquid mixtures. A primitive model (PM)-inspired system serves as a representative for asymmetric ionic materials (such as liquid crystalline salts) which quench to form disordered, partially-arrested phases. Self-Consistent Generalized Langevin Equation (SCGLE) Theory is applied to understand the connection between the size ratio of charge-matched salts and their average mobility. Within this model, we identify novel glassy states where one of the two charged species (either the macro-cation or the micro-anion) are arrested, while the other retains mobility. We discuss how this result is useful in the development of novel single-ion conducting phases in ionic liquid based materials.