Method for preparing high-purity lithium sulfide by using industrial-grade butyllithium

A method for preparing high-purity lithium sulfide by using industrial-grade butyllithium, comprising:

• step A:
• under an inert gas condition, thoroughly mixing 1.5-2.5 g of lithium chloride, 0.5 L of an industrial-grade n-butyllithium solution (2.5 mol/L), and 1.5-2.5 L of n-hexane to obtain a mixed solution, and charging the obtained mixed solution into a sealed container;
• step B:
• under the sealed condition, firstly introducing H2S gas into a gas-washing bottle through a submerged pipe at a rate of 10.5 L/h, then introducing into the mixed solution obtained in step A through the submerged pipe, controlling a reaction temperature at 25-40° C., and continuously stirring for reaction for 4-6 h to obtain a reaction slurry;
• step C:
• under an inert gas condition, filtering the slurry obtained by the reaction in step B above with a G3 sand core funnel to obtain a crude lithium sulfide solid wet material, and rinsing the crude lithium sulfide wet material three times with 0.5 L of dehydrated n-hexane;
• step D:
• under an inert gas condition, adding 0.5-1 L of pre-dehydrated NMP to the rinsed lithium sulfide wet material obtained in step C above, stirring for 1-2 h, and then filtering with a G3 sand core funnel to obtain a refined lithium sulfide wet material;
• step E:
• placing the refined lithium sulfide wet material obtained in step D into a vacuum drying oven, drying in vacuum at 205° C. for 8 h to obtain dried lithium sulfide;
• step F:
• placing the dried lithium sulfide obtained in step E into a vacuum-sealed stainless steel device, vacuumizing the device, placing the device into an atmosphere furnace at 550° C. followed by heat preservation for 2-4 h under an inert gas protection, and then naturally cooling to obtain high-purity lithium sulfide;
• and
• step G:
• crushing the high-purity lithium sulfide obtained after the heat treatment in step F above at 2000 r/min under an inert gas protection for 1-2 min to obtain a white anhydrous lithium sulfide powder, and performing vacuum packaging.