Mo-O Dual-Doped Argyrodite Electrolyte Enables Stable All-Solid-State Lithium Batteries

Sulfide solid electrolytes are one of the most promising solid electrolytes for all-solid-state lithium batteries due to their relatively high ionic conductivity and favorable mechanical properties. Nevertheless, their inferior moisture stability and lithium metal compatibility hinder the practical applications. Herein, a Mo-O dual-doped argyrodite Li₆P_{1- x}Mo_xS_{5-3 x}O_{3 x}Cl_{1+ x} sulfide electrolytes are synthesized to enhance both moisture stability and electrochemical characteristics. By adjusting the concentrations of dopant and annealing temperature, the optimized Li₆P_0.95Mo_0.05S_4.85O_0.15Cl_1.05 sintered at 570 °C exhibits enhanced room-temperature powder cold-pressed ionic conductivity of 3.97 mS cm^-1. Moreover, Li₆P_0.95Mo_0.05S_4.85O_0.15Cl_1.05 solid electrolyte produces only one-third of H₂S gas with 0.58 cm^-3 g^-1 compared to pristine Li₆PS₅Cl electrolyte and exhibits excellent structure stability after exposure to air. Benefitting from the generation of a stable Li₃OCl at the anode interface, Li₆P_0.95Mo_0.05S_4.85O_0.15Cl_1.05 solid electrolyte exhibits superior interfacial compatibility and suppression capability of lithium dendrites, realizing a high critical current density of 1.51 mA cm^-2 and maintains stable lithium plating/stripping behavior for 5600 h at 0.1 mA cm^-2 and 0.1 mAh cm^-2. In addition, the LiCoO₂/Li₆P_0.95Mo_0.05S_4.85O_0.15Cl_1.05/Li battery presents improved cycling stability at 1C with a capacity retention of 90.3% after 1000 cycles.