切割废硅粉球磨法制备锂离子电池负极材料

Preparation of anode material for lithium-ion battery from waste silicon powder by ball milling

硅碳复合材料被认为是最具潜力的下一代高能量密度锂离子电池负极材料。然而,当前锂离子电池负极用高品质硅碳材料的制备过程复杂、硅源成本高,造成其价格高昂,严重阻碍了硅碳复合材料在锂离子电池领域的规模化应用。以切割废硅粉为硅源、人造石墨为碳源,采用高能球磨法一步制备硅碳复合材料。系统研究了废硅粉的属性特征、硅碳复合材料的成分、微观结构,以及所制备硅碳复合微粉的电化学性能。结果表明,微米尺寸的废硅粉直接用于锂离子电池负极时其循环性能快速衰减,而采用球磨法制备的硅碳复合材料用于锂离子电池负极时则展现出优异的循环稳定性,在0.5 A/g电流密度下循环160圈后其可逆比容量仍然可以稳定在428 mA·h/g以上,较石墨负极比容量提升优势显著。

Silicon-carbon(Si-C)materials are considered to be the most promising next-generation high-energy-density lithium-ion battery(LIB)anodes.However,at present,the complex preparation process of high-quality Si-C anode materials for lithium-ion battery anodes and the high cost of Si raw materials result in high prices of Si-C materials,which seriously hinder the large-scale application of Si-C materials in the field of LIBs.In this paper,we use low-cost cutting waste Si powder as the Si source and graphite as the carbon source,and use a simple high-energy ball milling method to prepare waste Si powder-graphite composite material(WSi-G).The properties and characteristics of waste Si(WSi)powder,the microstructure of Si-C composites and their electrochemical properties were systematically studied.The results show that the cycle performance of micron-sized WSi is rapidly decayed when it is directly used as a LIB anode.Preparation of silicon carbon materials by ball milling exhibits excellent cycle stability when they are used in the anode of LIB,and the reversible specific capacity is stable above 428 mA·h/g at a current density of 0.5 A/g for 160 cycles,compared with graphite anode,the specific capacity is obviously improved.