(Invited) Modeling the Defect Chemistry, Transport Properties, and Stability of Antiperovskite Materials

Abstract

Solid-state electrolytes with fast lithium conduction are the core of the all-solid-state Li battery technology. By substituting the organic electrolyte with a piece of non-flammable ceramic material, we can achieve better safety, higher specific capacity, and a higher energy density. To date, the major bottleneck for this technology is the slow Li diffusion in the solid-state electrolyte and the interfacial incompatibility between the electrolyte and electrodes. To resolve these issues, several families of fast ionic conductors have been developed. The understanding of Li diffusion in these materials is essential to the development of novel family fast ionic conductors. To this end, atomistic modeling provides us with a unique tool to obtain comprehensive information on the atom motion, which is difficult to access with experimental techniques. In this talk, we showcase our group’s atomistic simulations regarding a novel family of superionic conductors, Li-rich anti-perovskites (LiRAPs) LiRAPs are a promising family of solid electrolytes, which exhibit ionic conductivities above 10-3 S cm-1 at room temperature, among the highest reported values to date. We first investigated the defect chemistry and the associated lithium transport in Li3OCl, a prototypical LiRAP, using DFT calculations and classical MD simulations [1]. We also studied the phase, interfacial, and voltage stability of these materials [2] with DFT, showing good agreement with experiments. Analogous simulations were also carried out for Na-rich anti-perovskites [3].