Investigation of the effect of O doping on the Li-ion mobility of Li3PS4 solid-state electrolytes: an ab initio molecular dynamics study

Abstract

Solid-state electrolytes have garnered attention as potential replacements for liquid organic electrolytes in lithium-ion batteries due to their inherent nonflammability and mechanical stability. In this study, the effect of O doping on the transport properties of Li₃PS₄ solid electrolytes was investigated using ab initio molecular dynamics (AIMD) simulations. The P–O bond is shorter than the P–S bond after O doping, providing more space for Li-ion migration, and making it easier for Li ions to migrate between tetrahedral Li, which was originally somewhat restricted. The diffusion coefficients of Li ions increase in all XYZ directions after doping, with the most significant improvement observed in the Y direction. Radial distribution function and bond length tracking revealed fast Li ion migration, while the PS₄ skeleton remained stable. Our results provide insights for the design of solid-state electrolytes through rational doping strategies.