Screening chloride Li‐ion conductors using high‐throughput force‐field molecular dynamics

Abstract

AbstractThe realization of high‐energy‐density all‐solid‐state Li‐ion batteries requires materials exhibiting both high Li‐ion conductivity and high deformability, as exemplified by Li3MCl6‐type chlorides. Herein, we optimized the classical force‐field (FF) parameters for 36 Li‐ and Cl‐containing compounds to reproduce the results of high‐precision first‐principles calculations and performed rapid FF molecular dynamics (MD) calculations to determine their Li‐ion conductivities. In addition, shear moduli were evaluated by first‐principles calculations and used as a deformability index. Li4Mn3Cl10 was selected based on its Li‐ion conductivity, stiffness, and thermodynamic stability. In accordance with the low calculated shear modulus (11.7 GPa), the cold‐pressed compact had a high relative density of 98%, which indicated good deformability. The room‐temperature conductivity (3.9 mS cm−1) was similar to that (1.6 mS cm−1) obtained by high‐precision first‐principles MD calculations. The Li‐ion conductivity of synthesized Li4Mn3Cl10 (18 µS cm−1) was relatively rather high compared to those of known chloride materials but much lower than the calculated value, which was ascribed to the fact that calculations were performed for the high‐temperature phase, whereas synthesis yielded the low‐temperature phase. The material screening method greatly increases the speed of material exploration and expands the application possibilities of chloride materials for all‐solid‐state batteries.