▎ 摘　　要

NOVELTY - Production of lithium sulfide involves (a) heat-treating lithium sulfate by mixing carbon-based material, and (b) obtaining lithium sulfide. The mixing ratio of aqueous lithium sulfate solution to the carbon-based material is 3:1 or more. USE - Production of lithium sulfide for producing high-purity lithium sulfide (claimed) used as raw material for sulfide-based solid electrolyte for lithium-sulfur battery. ADVANTAGE - The method is economically manufactured lithium sulfide with less impurities using lithium sulfate generated during lithium extraction process. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for high-purity lithium sulfide, which is mixed with the lithium sulfide and impurities. When the X-ray diffraction peak of lithium sulfide is 100%, the sum of X-ray diffraction peak ratio of impurities is 3% or less.