Oxygen- and Fluorine-Doped Li ₃ PS ₄ Glass-Ceramic Electrolytes Compatible with Lithium Metal Electrodes for All-Solid-State Batteries

High Resolution Image Download MS PowerPoint Slide Sulfide-based all-solid-state lithium metal batteries are considered promising next-generation energy storage devices owing to their safety and high energy densities. However, short-circuiting caused by Li dendrite growth hinders their practical applications. Hence, developing solid electrolytes that have high reduction tolerance and ionic conductivity is essential to avoid cell failure. In this study, Li 3 PS 4– x O x ·LiF glass-ceramic electrolytes were synthesized by partially substituting S with O to improve reduction tolerance. The oxygen-substituted Li 3 PS 3.8 O 0.2 ·LiF glass precipitated a high-temperature α-Li 3 PS 4 analog phase through crystallization via a conventional slow heating–cooling process, without requiring rapid heating–cooling. The Li 3 PS 3.8 O 0.2 ·LiF glass-ceramic electrolyte exhibited a high conductivity of 1.3 × 10 –3 S cm –1 at room temperature. Furthermore, a reaction layer was hardly observed at the Li metal interface after cycling, suggesting that the Li 3 PS 3.8 O 0.2 ·LiF glass-ceramic electrolyte has excellent reduction tolerance. These findings emphasize the critical role of achieving both high reduction tolerance and high ionic conductivity in designing solid electrolytes for Li metal batteries.