Design Rules for Selecting Suitable Weakly Solvating Electrolytes for Lithium Metal Batteries

Abstract

Weakly solvating electrolyte (WSE) is a promising and convenient strategy to regulate Li⁺ solvation structures and promote the formation of an anion-driven and robust solid electrolyte interface layer. Here, we outline a reasonable workflow to realize high-throughput calculations of the binding energy of Li⁺-solvent in a stable conformation and molecular polarity index (MPI) of solvents to replace the value of donor number and dielectric constants, which are difficult to obtain experimentally. Twenty-six common solvent molecules are used to verify the workflow. Based on the output (binding energy and MPI value), we construct a descriptor (named W_s) that is suitable to screen WSE and verify it in 6 typical solvent systems through experiments, molecular dynamic (MD) simulations, and survival probability function. This work demonstrates a universal and useful strategy to distinguish potential solvents for the WSE system and can also be developed for other battery systems in the future.