▎ 摘　　要

NOVELTY - Preparing lithium sulfide comprises mixing lithium source and first sulfur source to obtain first mixture, heating the first mixture from a first temperature to a second temperature at a predetermined pressure, micro-gap filling by a gaseous carbon source in a micro-flow state, where the micro-gap filling includes heating the precursor forming the cladding layer to the third temperature under an inert atmosphere, intruding gaseous carbon source into a material column, and continuing to heat less than fourth temperature. USE - The lithium sulfide is useful as raw material for synthesis of sulfide solid-state electrolytes in lithium-sulfur battery anode materials or all-solid-state batteries (claimed). ADVANTAGE - The lithium sulfide: adopts a secondary heating scheme, and ensures the solid raw materials are only elemental sulfur and metal lithium, and no other impurities are introduced, which effectively solves the problem of low purity of lithium sulfide when used in lithium-sulfur solid-state batteries, reduces the possibility of lithium sulfide absorbing moisture and being oxidized and improves the overall performance of the lithium sulfide composite material; and further improves the charging and discharging speed in lithium sulfide battery.