Sulfide solid electrolytes for all-solid-state Lithium batteries: Classification, synthesis, moisture stability, interfacial engineering, and scalable manufacturing

Sulfide solid electrolytes (SSEs) combine room temperature ionic conductivities of approximately 10 −3 to 10 −2 S·cm −1 with favorable mechanical formability, making them promising electrolytes for all-solid-state lithium batteries. However, their practical application remains limited by moisture degradation and H 2 S release, restricted thermodynamic stability, electrode interface reactions, and challenges in scalable processing. This review first classifies sulfide solid electrolytes into glassy, glass-ceramic, thio-LISICON, Li 10 GeP 2 S 12 (LGPS) type, and lithium argyrodite systems, and compares their structures, Li + transport characteristics, stability, and practical advantages and limitations. It then examines phase formation and the relationship between processing and performance in solid state, mechanochemical, and liquid phase synthesis. Moisture degradation mechanisms, H 2 S evolution, stabilization strategies, and manufacturing-related control measures are subsequently discussed. Particular attention is further given to anode interface modification, including artificial interphases, alloy and composite anodes, and chemical and mechanical regulation, as well as cathode interface modification using oxide, phosphate, halide, sulfide, and boron-based coatings. Finally, raw material cost, solvent recycling, thin electrolyte membranes, continuous manufacturing, and operation under low stack pressure are assessed. By comparing ionic conductivity, H 2 S release, interfacial impedance, current density, areal capacity, stack pressure, and cycle life under their respective test conditions, this review identifies the key factors governing the translation of material performance into practical cell performance and provides an engineering framework for reproducible and scalable sulfide-based all-solid-state batteries (ASSBs).