The invention provides
lithium sulfide, a preparation method thereof and a
solid-state battery, and belongs to the technical field of batteries, and the preparation method of the
lithium sulfide comprises the following steps: performing hydrosulfide reaction on water-containing hydrosulfide and
lithium salt dissolved in a first
solvent under the protection of
inert gas to obtain a first lithium hydrosulfide suspension, and performing
solid-liquid separation to obtain a first lithium hydrosulfide solution, the first
solvent comprises an aprotic polar
organic solvent; decompressing and
dewatering the first lithium hydrosulfide solution to obtain a second lithium hydrosulfide suspension, and performing
solid-liquid separation to obtain a second lithium hydrosulfide solution in which the
water content is 0.05-2%; and desulfurizing the second lithium hydrosulfide solution to obtain a
lithium sulfide suspension, and carrying out solid-liquid separation to obtain
lithium sulfide. According to the present invention, the low-cost water-containing hydrosulfide is selected as the
raw material, the pressure reducing water removal process is added to remove the impurities, and then the desulfurization is performed to obtain the high-purity
lithium sulfide;