Influence of Surfaces on Ion Transport and Stability in Antiperovskite Solid Electrolytes at the Atomic Scale

Antiperovskites are generating considerable interest as potential solid electrolyte materials for solid-state batteries because of their promising ionic conductivity, wide electrochemical windows, stability, chemical diversity and tunability, and low cost. Despite this, there is a surprising lack of a systematic study of antiperovskite surfaces and their influence on the performance of these materials in energy storage applications. This is rectified here by providing a comprehensive density functional theory investigation of the surfaces of M3OX (M = Li or Na; X = Cl or Br) antiperovskites. Specifically, we focus on the stability, electronic structure, defect chemistry, and ion transport properties of stable antiperovskite surfaces and how these contribute to the overall performance and suitability of these materials as solid electrolytes. The findings presented here provide critical insights for the design of antiperovskite surfaces that are both stable and promote ion transport in solid-state batteries.