High Capacity and Superior Cyclic Performances of All-Solid-State Lithium–Sulfur Batteries Enabled by a High-Conductivity Li₁₀SnP₂S₁₂ Solid Electrolyte

All-solid-state lithium–sulfur batteries (ASSLSBs) employing sulfide-based solid electrolytes have gained widespread attention for their high energy density and intrinsic safety. Li10SnP2S12 is identified as one of the most rivaling candidates in sulfide electrolytes. Herein, a highly Li-ion-conductive Li10SnP2S12 solid-state electrolyte (SSE) is synthesized via a combination of high-energy ball-milling and heat treatment processes, which is more facile and efficient compared with other previously reported methods. The obtained Li10SnP2S12 SSE exhibits high ionic conductivity (3.2 × 10–3 S cm–1) at room temperature (RT). The effects of the annealing temperature on the Li-ion conductivity and activation energy of Li10SnP2S12 are also thoroughly studied. Moreover, the ASSLSBs based on the Li10SnP2S12 electrolyte are constructed, and they deliver a high initial capacity of 1601.7 mAh g–1 at 40 mA g–1. A favorable capacity retention upon cycling and a good rate performance are also achieved at RT. Concomitantly, the Coulombic efficiency approaches 100% during the prolonged cycling. This work tremendously accelerates the practical applications of the Li10SnP2S12 SSE among the emerging high-energy ASSLSBs.