Si-doped composite carbon as anode of lithium ion batteries

Si-doped composite material was prepared by coating artificial graphite with the mixture of phenol resin and polysilicone and following with heat-treatment at 1050°C in argon atmosphere. The structure and characteristics of the composite carbon were determined by means of XRD, SEM, BET surface area and electrochemical measurements. The new carbon material has a disordered carbon/graphite composite structure, with silicon doped in the disordered carbon. Compared with the pristine graphite, the electrochemical performance is improved for the Si-doped composite carbon with large reversible capacity of 312.6 mAh/g, high initial charge/discharge efficiency of 88.61%, and excellent cycle stability. The prototype batteries using the composite carbon as anode material have large discharge capacity of 845 mAh and high capacity retention ratio of 95.80% at the 200th cycle.