Electrochemical investigation of silicon/carbon composite as anode material for lithium ion batteries

Silicon-graphite composites were prepared by mechanical ball milling for 20 h under argon protection. The microstructure and electrochemical performance of the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy, and electrochemical experiments. XRD showed that the materials prepared by ball milling were composites consisting of Si and graphite powders. The composite electrode showed the best performance, especially when annealed at 200 C for 2 h, which had a reversible capacity of 595 mAh g-1 and an initial coulombic efficiency of 66%, and still retained 469 mAh g-1 after 40 cycles with about 0.6% capacity loss per cycle.