Si/C composite negative electrode material for lithium ion batteries

A novel Si/C composite negative electrode for lithium ion batteries was obtained by pyrolyzing the mixture of polyvinyl chloride, nano-Si powder and fine artificial graphite particles. Nano-Si and fine graphite are dispersed in carbon uniformly. Electrochemical test shows the first cycle efficiency of the composite is about 84% and the reversible capacity is about 700 mAh.g(-1). The capacity retention at the 30th cycle is more than 90%. In addition, the charge-discharge voltage plateau of the composite shifts toward positive direction for about 0.15 V against that of the commercialized CMS negative electrode material, which is favorable for enhancing the charging rate and operating safety of the cell.