Core-shell Si/C nanocomposite as anode material for lithium ion batteries

We report an effective method for the synthesis of a core-shell Si/C nanocomposite, and its application as anode material for lithium ion (Li-ion) batteries. Polyacrylonitrile (PAN)-coated Si nanoparticles are formed by emulsion polymerization, and this precursor is heat-treated under argon to generate a Si/C core-shell nanocomposite. The conductive carbon shell envelops the silicon nanoparticles and suppresses aggregation of the nanoparticles during cycling. Meanwhile, the carbon shell combines closely with the nanocores, and significantly enhances the kinetics of lithium intercalation and de-intercalation, as well as the apparent diffusion coefficient of Li-ions. Consequently, the core-shell Si/C nanocomposite exhibits better electrochemical performance than pure Si nanoparticles, indicating that this is a promising approach to improve cyclability and kinetics of nano-anode materials for Li-ion batteries.