SOLID ELECTROLYTE FOR LITHIUM SECONDARY BATTERY WITH NOVEL CRYSTAL STRUCTURE AND METHOD FOR PRODUCING THE SAME

A solid electrolyte for a lithium secondary battery having a novel crystal structure and a method for producing the same is provided. The solid electrolyte has excellent lithium-ion conductivity and is chemically stable. The solid electrolyte comprises lithium (Li), germanium (Ge), and sulfur (S), forming a ternary compound with GeSpolyhedra and GeStetrahedra in a unit cell. The electrolyte may include compounds such as LiGeSand demonstrates lithium-ion conductivity of at least 8.7×10S·cmat 25° C. Production methods involve either milling lithium and germanium sulfides to form an amorphous intermediate material, followed by heat treatment, or using crystalline raw materials like LiGeSand LiGeSdirectly. Both methods produce a stable, high-conductivity solid electrolyte suitable for all-solid-state lithium batteries, addressing safety and performance limitations of conventional electrolytes.