Working Potential of Sulfide based Solid-Electrolyte having High Critical Current Density

Sulfide solid-state electrolytes owing to their high ionic conductivity, and suitable mechanical properties are promising to develop all-solid-state lithium metal batteries (ASLBs) with higher energy density (WhKg^-1) and practical safety. However, their practical integration into ASLBs is hindered by poor electrochemical stability with Li metal anode/high-voltage cathodes and low critical current density (CCD). Herein, we report a novel metal halide doped Lithium phosphorus sulfide electrolyte (Li₇P₃S_11-xAY_n, where AY_n is a metal halide) having CCD greater than 2 mAcm-2 at ambient temperature. The ionic conductivity was increased noticeably i.e., from 2.9 × 10^-4 Scm^-1 for the pristine one (Li₇P₃S₁₁) to 3.7 × 10^-4 Scm^-1 for the concentration-optimized doped one. Also, symmetrical Li/Li cells with an optimized dopant concentration of AY_n-doped electrolyte showed extended cycling stability as compared to the pristine electrolyte under a current density of 0.1 mAcm^-2. Our work provides a novel strategy for sulfide electrolytes with suppressed dendrites penetration even at comparatively higher current densities, which has integration potential to advance the development of ASSLBs.