O-doping strategy enabling enhanced chemical/electrochemical stability of Li3InCl6 for superior solid-state battery performance

Solid-state electrolytes with high oxidation stability are crucial for achieving high power density all-solid-state lithium batteries. Halide electrolytes are promising candidates due to their outstanding compatibility with cathode materials and high Li+ conductivity. However, the electrochemical stability of chloride electrolytes is still limited, leaving them unsuitable for ultrahigh voltage operation. Besides, chemical compatibility issue between sulfide and halide electrolytes affects the electrochemical performance of all-solid-state batteries. Herein, Li-ion conductor Li3+xInCl6−xOx is designed to address these challenges. Li3.25InCl5.75O0.25 shows a Li-ion conductivity of 0.90 mS cm−1 at room temperature, a high onset oxidation voltage of 3.84 V, fewer by-products at ultrahigh operation voltage, and good chemical compatibility with Li5.5PS4.5Cl1.5. The Li3.25InCl5.75O0.25@LiNi0.7Co0.1Mn0.2O2-Li3.25InCl5.75O0.25-VGCF/Li3.25InCl5.75O0.25/Li5.5PS4.5Cl1.5/Li-In battery delivers good electrochemical performances at high operating voltage. This work provides a simple, economical, and effective strategy for designing high-voltage all-solid-state electrolytes.