METHOD FOR PRODUCING LITHIUM SULFIDE
A method for producing lithium sulfide is provided, including a firing step of firing lithium carbonate in an atmosphere containing sulfur gas and hydrogen gas. The sulfur gas is contained in the atmosphere in such a manner that the value of the number of moles of sulfur element with respect to the number of moles of lithium carbonate is from 6.0 to 19.0. The hydrogen gas is preferably contained in such a manner that the value of the number of moles of hydrogen gas with respect to the number of moles of lithium carbonate is from 8.5 to 12.0. The firing step is preferably a step of firing lithium carbonate, while circulating a mixed gas containing sulfur gas and hydrogen gas inside a heating furnace in which the lithium carbonate is placed.
1 . A method for producing lithium sulfide, comprising:
a firing step of firing lithium carbonate in an atmosphere containing sulfur gas and hydrogen gas,
wherein the sulfur gas is contained in the atmosphere in such a manner that a value of the number of moles of sulfur element with respect to the number of moles of lithium carbonate is from 6.0 to 19.0.
2 . The method for producing lithium sulfide according to claim 1 , wherein the hydrogen gas is contained in such a manner that a value of the number of moles of hydrogen gas with respect to the number of moles of lithium carbonate is from 8.5 to 12.0.
3 . The method for producing lithium sulfide according to claim 1 , wherein the firing step comprises firing lithium carbonate while circulating a mixed gas containing sulfur gas and hydrogen gas inside a heating furnace in which the lithium carbonate is placed.
4 . The method for producing lithium sulfide according to claim 1 , wherein the firing step comprises firing lithium carbonate while circulating a mixed gas containing sulfur gas and hydrogen gas that is diluted with an inert gas inside a heating furnace in which the lithium carbonate is placed.
5 . The method for producing lithium sulfide according to claim 3 , wherein the mixed gas is circulated inside the heating furnace after a temperature in the heating furnace reaches 650° C. or higher.
6 . The method for producing lithium sulfide according to claim 4 , wherein the inert gas is circulated inside the heating furnace until a temperature in the heating furnace reaches 650° C.
7 . The method for producing lithium sulfide according to claim 1 , wherein the firing step comprises firing lithium carbonate in such a manner that the lithium sulfide has, in an X-ray diffraction pattern as measured using an X-ray diffraction apparatus using CuKα1 rays, a value of I b to I a of 0.024 or less, wherein
the I a is an intensity of a diffraction peak A and the Ip is an intensity of a diffraction peak B, the peak A being a diffraction peak at the position of 2θ=31.2°±1.0° and the peak B being a diffraction peak at the position of 2θ=21.3°±1.2°.
8 . The method for producing lithium sulfide according to claim 1 , wherein the firing step comprises firing lithium carbonate in such a manner that the lithium sulfide has, in an X-ray diffraction pattern as measured using an X-ray diffraction apparatus using CuKα1 rays, a value of I c to I a of 0.19 or less, wherein
the I a is an intensity of a diffraction peak A and the I c is an intensity of a diffraction peak C, the peak A being a diffraction peak at the position of 2θ=31.2°±1.0° and the peak C being a diffraction peak at the position of 2θ=22.2°±1.0°.
9 . The method for producing lithium sulfide according to claim 1 , further comprising a reaction step of reacting the lithium sulfide obtained in the firing step with hydrogen gas.
10 . The method for producing lithium sulfide according to claim 9 , wherein the reaction step comprises circulating hydrogen gas inside a heating furnace in which the lithium sulfide is placed, and heating the heating furnace.
11 . The method for producing lithium sulfide according to claim 9 , wherein the hydrogen gas is diluted with an inert gas.
12 . The method for producing lithium sulfide according to claim 10 , wherein the reaction step comprises heating the heating furnace to 800° C. or higher.