Charting the known chemical space for non-aqueous Lithium-air battery electrolyte solvents

TL;DR

This study systematically explores the chemical space of potential electrolyte solvents for Lithium-air batteries, emphasizing the importance of balancing solubility and viscosity, and proposes a transferable screening approach for electrolyte optimization.

Contribution

It introduces a comprehensive computational screening method that considers multiple properties and explores full chemical sub-spaces, advancing beyond current state-of-the-art in electrolyte design.

Findings

Optimal electrolyte solvents require balancing solubility and viscosity.

Full chemical sub-space exploration improves candidate identification.

The screening approach is applicable to other electrochemical devices.

Abstract

The Li-Air battery is a very promising candidate for powering future mobility, but finding a suitable electrolyte solvent for this technology turned out to be a major problem. We present a systematic computational investigation of the known chemical space for possible Li-Air electrolyte solvents. It is shown that the problem of finding better Li-Air electrolyte solvents is not only - as previously suggested - about maximizing Li+ and O2- solubilities, but about finding the optimal balance of these solubilities with the viscosity of the solvent. As our results also show that trial-and-error experiments on known chemicals are unlikely to succeed, full chemical sub-spaces for the most promising compound classes are investigated, and suggestions are made for further experiments. The proposed screening approach is transferable and robust and can readily be applied to optimize electrolytes for other electrochemical devices. It goes beyond the current state-of-the-art both in width (considering the number of compounds screened and the way they are selected), as well as depth (considering the number and complexity of properties included).