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 degrees 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. (C) 2010 Elsevier B.V. All rights reserved.