Cl- and Al-Doped Argyrodite Solid Electrolyte LiPSCl for All-Solid-State Lithium Batteries with Improved Ionic Conductivity.

Argyrodite solid electrolytes such as lithium phosphorus sulfur chloride (LiPSCl) have recently attracted great attention due to their excellent lithium-ion transport properties, which are applicable to all-solid-state lithium batteries. In this study, we report the improved ionic conductivity of an argyrodite solid electrolyte, LiPSCl, in all-solid-state lithium batteries via the co-doping of chlorine (Cl) and aluminum (Al) elements. Electrochemical analysis was conducted on the doped argyrodite structure of LiPSCl, which revealed that the substitution of cations and anions greatly improved the ionic conductivity of solid electrolytes. The ionic conductivity of the Cl- and Al-doped LiPSCl (LiAlPSCl) electrolyte was 7.29 × 10 S cm at room temperature, which is 4.7 times higher than that of LiPSCl. The Arrhenius plot of the LiAlPSCl electrolyte further elucidated its low activation energy at 0.09 eV.