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

Abstract

ABSTRACT 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 N 2 , O 2 , and CO 2 . Both Li 6 PS 5 Cl and Li 5.4 PS 4.4 Cl 1.6 exhibit chemical inertness toward N 2 , but easily react with O 2 and CO 2 . Notably, Li 5.4 PS 4.4 Cl 1.6 shows inferior stability against O 2 and CO 2 compared to Li 6 PS 5 Cl, attributed to the weakness of P─Cl bond in the PS 3 Cl motif as confirmed by density functional theory calculations. Nevertheless, oxygen doped Li 6.05 PS 4.9 O 0.1 Cl 1.05 and Li 5.3 PS 4.2 O 0.2 Cl 1.5 possess more positive free energy changes towards O 2 and CO 2 oxidation, thereby suppressing the decomposition of PS 4 3− units. In addition, Li 5.3 PS 4.2 O 0.2 Cl 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 5.3 PS 4.2 O 0.2 Cl 1.5 and lithium metal enables stable cycling for 10 000 h at 0.1 mA cm −2 . The resultant LiNbO 3 @LiCoO 2 |Li 5.3 PS 4.2 O 0.2 Cl 1.5 |Li battery retains 81.6% of its initial capacity after 1000 cycles at 1 C, and the LiNbO 3 @LiCoO 2 ||Li pouch cell with Li 5.3 PS 4.2 O 0.2 Cl 1.5 membrane delivers 86.6% capacity retention after 250 cycles at 0.1 C.