Influence of nano-crystallization on Li-ion conductivity in glass Li _3 PS _4 : a molecular dynamics study

Understanding the ionic conduction mechanisms in solid electrolyte glasses and glass-ceramics is an important task for improving the performance of next-generation all-solid-state batteries. Although many ionic conduction mechanisms have been proposed, the mechanism of increased ionic conductivity in partially crystallized glass is not fully understood. In this study, molecular dynamics was used to analyze the strain and local ion mobility in the glass around the crystal nano-particles of Li _3 PS _4 , which is a promising material for solid electrolytes. From the analysis of the results, we find that a local strain field is generated around the crystal particles and that the tensile strain field decreases the activation energy of ion migration and increases the ionic conductivity. This study opens the possibility of improving the ionic conductivity of glass-ceramics by controlling crystallization and dispersing the tensile strain field, even though the crystalline phase is not a high ionic conducting phase.