具有核壳结构的锂离子电池用Sn/C复合负极材料研究

Research on Sn/Carbon Compound Anode Materials with Core-Shell Structure for Lithium Ion Battery

采用碳热还原法以及沥青裂解包覆技术,制备具有核壳结构的Sn/C复合负极材料,对采用改性天然石墨与人造石墨作为内核的效果作了比较,并分析研究壳层的厚度对材料综合性能的影响。结果表明,采用改性天然石墨作为内核能更有效分散Sn金属颗粒,另外沥青裂解碳包覆层的厚度对材料的循环稳定性具有较大的影响。以改性天然石墨为内核,具有(10%+20%)双层包覆结构的负极样品具有最佳的综合性能,首次库伦效率为76.3%,54周的容量保持率为99%。材料结构的设计以及结构的合成工艺是解决锡基合金负极材料体积效应的重要途径。

With the method of carbon thermal reduction and asphalt pyrolysis coating,a new Sn/C anode material for lithium ion battery was synthesized with core-shell structure.The comparison of modified natural graphite and artificial graphite used as core was carried out,and the influence on the cyclic performance from the thickness of the shell was studied.The results showed that using modified natural graphite as core got better dispersion of Sn particles,and the thickness of the asphalt coating played an important part on the cyclic performance.The sample using modified natural graphite as core with（10%＋20%）two layers asphalt coating exhibited the best performance,whose initial cyclic efficiency was 76.3%,and the rate of capacity retention was 99% after 54 cycles.Consequently,a right structure and an appropriate treatment are keys to solve the problem of expansion and pulverization during the charge and discharge process.