Argyrodite Sulfide Electrolytes with Dry Atmospheric Stability for All-Solid-State Lithium Batteries

The instability of sulfide electrolytes toward air and their incompatibility with solvents remain a great challenge that hampers their scalable manufacturing for all-solid-state lithium batteries. In this work, the effects of major components in air on argyrodite sulfide electrolytes are systematically investigated, including N₂, O₂, and CO₂. Both Li₆PS₅Cl and Li_5.4PS_4.4Cl_1.6 exhibit chemical inertness toward N₂, but easily react with O₂ and CO₂. Notably, Li_5.4PS_4.4Cl_1.6 shows inferior stability against O₂ and CO₂ compared to Li₆PS₅Cl, attributed to the weakness of P─Cl bond in the PS₃Cl motif as confirmed by density functional theory calculations. Nevertheless, oxygen doped Li_6.05PS_4.9O_0.1Cl_1.05 and Li_5.3PS_4.2O_0.2Cl_1.5 possess more positive free energy changes towards O₂ and CO₂ oxidation, thereby suppressing the decomposition of PS₄ ^3- units. In addition, Li_5.3PS_4.2O_0.2Cl_1.5 also shows excellent tolerance to sec-butyl acetate, realizing a 12 µm-thick membrane with high ionic conductivity of 2.34 mS cm^-1 by wet-coating process. Moreover, the improved interface compatibility between Li_5.3PS_4.2O_0.2Cl_1.5 and lithium metal enables stable cycling for 10 000 h at 0.1 mA cm^-2. The resultant LiNbO₃@LiCoO₂|Li_5.3PS_4.2O_0.2Cl_1.5|Li battery retains 81.6% of its initial capacity after 1000 cycles at 1 C, and the LiNbO₃@LiCoO₂||Li pouch cell with Li_5.3PS_4.2O_0.2Cl_1.5 membrane delivers 86.6% capacity retention after 250 cycles at 0.1 C.