A molecular perspective on coordination, screening, and emergent length scales in lithium electrolytes

TL;DR

This paper presents a unified multiscale framework for understanding lithium electrolytes, linking local coordination, mesoscale organization, and macroscopic transport, especially at high concentrations where these phenomena are coupled.

Contribution

It introduces a comprehensive physical model that integrates coordination chemistry, ionic clustering, and collective dynamics in concentrated electrolytes.

Findings

Increasing concentration leads to a transition from solvent-dominated coordination to ion pairing and clustering.

Screening and transport phenomena are interconnected through correlated ionic structures.

Designing better electrolytes requires controlling coordination, mesoscale organization, and electrostatic response simultaneously.

Abstract

Lithium electrolytes are commonly described using separate conceptual frameworks for local coordination chemistry, electrostatic screening, and ionic transport. This separation is effective in dilute conditions but breaks down at higher concentration, where coordination, ion pairing, clustering, and collective dynamics become intrinsically coupled. In this Perspective, we develop a unified multiscale framework that links local coordination motifs, mesoscopic ionic organization, and macroscopic transport within a single physical picture. Through representative examples spanning carbonate liquids, polymer electrolytes, concentrated systems, and confinement, we show that increasing concentration drives a systematic evolution from solvent-dominated Li$^+$ coordination to ion pairing, clustering, and correlated domains. In this regime, screening and transport are not independent phenomena but arise from the same underlying correlated structures. This perspective implies that rational electrolyte design must simultaneously control short-range coordination, mesoscale organization, and collective electrostatic response.