Origin of Fast Ion Conduction in Na<sub>3</sub>PS<sub>4</sub>: Insight from Molecular Dynamics Study
Kartik Sau, Tamio Ikeshoji
Abstract
Na3PS4 has received significant attention as a solid electrolyte for use in all-solid-state batteries because of its high ionic conductivities. In this work, we performed a series of molecular dynamics simulations using a refined set of potential parameters to study the origin of the high conductivity in the recently reported γ-phase. The potential model successfully reproduced the structural and dynamical behavior of the system. Importantly, it could reproduce the high- to low-temperature phase transition. This study revealed that the cationic conductivity was enhanced by 4–5 orders of magnitude because of anionic reorientational motion, which generated disordered cationic sites at the γ-phase. These findings are of fundamental interest in fast ion-conducting solids and for tailoring their properties.