Abstract:Lithium sulfide is an essential raw material for the synthesis of sulfur-based solid electrolytes, and its purity plays a key role in the improvement of electrolyte materials and battery performance. In this paper, the method of high-temperature pyrolysis was used to prepare high-purity lithium sulfide, the mechanism of the main reaction was analyzed through thermodynamic calculation, and the influence of calcination temperature and time on the main content and impurity content was investigated. The results show that the main reaction of lithium sulfate and carbon proceeded more thoroughly when the calcination temperature is higher than 660 ℃ and Log K>5. The calcination temperature has a greater influence on the main content and carbonate content of the product. Under the conditions of calcination temperature 775 ℃, time 1.5 h and equimolar ratio (Li₂SO₄: sucrose=1/1), the main content of the product can be as high as 99.9%.