锂离子电池Si/C复合负极材料的合成与性能

采用球磨-热解工艺制备了Si/C复合负极材料。研究了球磨时间对Si/C复合负极材料结构和电化学性能的影响,并分析了电极的失效机理。研究结果表明,通过球磨可以将纳米硅颗粒均匀分散于石墨基体材料表面,同时,葡萄糖热解后形成的无定形碳使两者紧密结合。球磨3h合成的材料具有最优的电化学性能。以100mA/g的电流密度放电,首次放电容量达到1340mAh/g,首次充放电效率为75.6%,循环50次后,容量保持率为34.2%。

Synthesis and Properties of Si/C Composites as Anode Materials for Lithium-Ion Batteries

The composites as anode materials were fabricated by ball milling and thermal decomposition.The influence of ball milling time on the structure and electrochemical performance of Si/C composites was investigated,and the failure mechanism of this Si/C electrode was also analyzed.The research results show that nano silicon particles can be homogeneously dispersed on the surface of the graphite base material though ball milling,at the same time, amorphous carbon obtained from glucose can makes them closely combined after thermal decomposition.The compo-site prepared by ball milling for 3 h shows the best electrochemical properties.The first discharge capacity of Si/C composites can reach 1340 mAh/g at 100 mA/g,and its first charge/discharge efficiency is 75.6%.After 50 cycles, the capacity retention rate is 34.2%.