First-Principles Investigations on Sodium Superionic Conductor Na11Sn2PS12

Sodium superionic conductors are key components of solid-state sodium ion batteries, which are regarded as promising alternative energy storage options for large-scale application. Recently, a new crystalline sodium superionic conductor Na 11 Sn 2 PS 12 was reported with a remarkably high ionic conductivity over 1 mS/cm at room temperature. Herein, we report the comprehensive first-principles investigations on this new sodium superionic conductor. Our ab initio molecular dynamics simulations confirm the intrinsically fast and isotropic diffusion of sodium ions in Na 11 Sn 2 PS 12 involving all the sodium sites. From a series of first-principles calculations, we propose a sodium diffusion mechanism and discuss the effects of various defects or substitutions on the diffusion kinetics, which may aid in further development of this class of materials. Moreover, we argue that the inherent vaca…