Microstructure and electrochemical performance of Si–SiO2–C composites as the negative material for Li-ion batteries

Si–SiO2–C composites are synthesized by ball milling the mixture of SiO, graphite and coal pitch, and subsequent heat treatment at 900 °C in inert atmosphere. The electrochemical performance and microstructure of the composites are investigated. XRD and TEM tests indicate that the carbon-coating structure of Si–SiO2–C composites form in pyrolysis process, which can remarkably improve the electrochemical cycling performance. The coal pitch as carbon precursor and graphite demonstrate the same important effect on the Li-alloying/de-alloying property of the Si–SiO2–C composites. The Si–SiO2–C composites exhibit the electrochemical reversible Li-alloying/de-alloying capacity of 700 mAh g−1 and excellent cyclic stability even at about the 90th cycle.