China Nonferrous Metallurgy

The preparation of lithium sulfide composite graphite materials is a hot topic for many scholars, and how to prepare high-capacity lithium sulfide composite graphite structural materials is of more research significance. At present, the method of graphite thermal reduction of lithium sulfate is used to produce this material on an industrial scale. The process requires a high-temperature system and belongs to a solid phase reaction. The reaction rate and particle size are limited by lithium sulfate. In this paper, the idea of preparing lithium sulfide/graphite composite cathode material by using high temperature to immerse lithium into a cheap graphite layer in a vacuum system and sulfurizing in the same system is proposed. The effects of various parameters on the lithium volatilization rate and lithium filling rate of the prepared materials were investigated. The main conclusions are as follows: The optimum leaching process parameters are the leaching temperature of 1173K and the time of 180min. The optimum vulcanization process parameters are the vulcanization temperature of 453K and the time of 40min. The reaction process is in a vacuum system, which not only stabilizes the highly active lithium but also improves the reaction degree of lithium and sulfur. The lithium immersed in graphite is protected and the lithium size is limited to the micron level. The lithium in the prepared lithium sulfide/graphite composite cathode material is basically in the graphite interlayer, and the content of lithium sulfide in the product is 78.88%. The structure of lithium sulfide/graphite composite is more conducive to electron conduction. It is used as a positive electrode for energy storage tests. The barrier is only 3.0V, and the specific capacity is as high as 921.6mAh/g.