A method for synergistically preparing
lithium sulfide by vacuum
molten salt based on
hydrogen sulfide-
lithium salt reaction belongs to the technical field of battery materials, and comprises the following steps: placing a
lithium salt
solid in a reactor, introducing a
molten salt medium on the surface of the lithium salt or in a
reaction system, introducing purified
hydrogen sulfide gas under a vacuum auxiliary condition, controlling the
reaction temperature to be 200-500 DEG C, and reacting for 1-2 hours; and adjusting the flow rate of
hydrogen sulfide to be 50-1000mL / min and the
retention time to be 5-180min, continuously exhausting gas to
discharge water vapor in the reaction process, stopping introducing
hydrogen sulfide gas after the reaction is finished, cooling the
system to
room temperature under the protection of
inert gas, taking out the product, washing to remove residual fused salt, and carrying out
vacuum drying to obtain the high-purity
lithium sulfide. The prepared
lithium sulfide has high purity (greater than or equal to 99.90%), low defect density and an excellent
crystal structure, and can be widely applied to lithium-
sulfur batteries, all-
solid-state batteries and novel
energy storage technologies, so that the
energy density is improved, the cycle life is prolonged, and the
energy consumption is reduced.