High performance silicon/carbon composite prepared by in situ carbon-thermal reduction for lithium ion batteries

Silicon/carbon composite was prepared by an in situ carbon-thermal reduction method that used pyrolyzed carbon to reduce silicon monoxide. The composite was confirmed by X-ray diffraction and high-resolution transmission electron microscope. It was demonstrated that nano-scale (ca. 20 nm) crystal silicon particles were obtained and simultaneously distributed in amorphous carbon matrix. Compared with the silicon/carbon composite having commercial nano-silicon particles (50-100 nm), the as-prepared composite displayed a good capacity retention. The superior electrochemical properties were attributed not only to small volume changes of silicon particles, but also to better buffering effect of matrix and better electrical contact between the matrix and silicon particles. (C) 2010 Elsevier B.V. All rights reserved.