Spatial-Decomposition Analysis of Electrical Conductivity in Mixtures of Ionic Liquid and Sodium Salt for Sodium-Ion Battery Electrolytes

Ionic liquid (IL)-based electrolytes are a promising material for the development of sodium-ion batteries, and their performance can be quantified by electrical conductivity. In this highly concentrated ionic system, the correlated motions of ion pairs are influential on the ionic transport properties. Herein, all-atom analyses are conducted through molecular dynamics simulations to bridge the macroscopically observable electrical conductivity with the molecular pictures of correlated motion of ion pairs. The analysis is applied to three mixtures of IL with sodium salt that are relevant to the electrolyte for a sodium-ion battery: [1-ethyl-3-methylimidazolium, Na][bis(fluorosulfonyl)amide] ([C