Core–shell structured C/SiO2 composites derived from Si-rich biomass as anode materials for lithium-ion batteries

Lignin and ash are the main factors to limit integrated utilization of Si-rich biomass. In this study, core–shell structured lignin-SiO2 composites are prepared from rice husks (RHs) by alkali extraction and acid precipitation and applied as the precursors of anode materials to achieve efficient application. Alkaline lignin is employed to supplement carbon to improve electrochemical performance of C/SiO2 composites. The optimal sample C/SiO2-6 possesses integrated coating shells and appropriate carbon content (38.27%), resulting in stable cycling performance and high capacity retention of 534 mA h g−1 at 1 A g−1 after 1000 cycles, close to 574 mA h g−1 of the C/SiO2 composite synthesized by commercial raw materials. Meanwhile, C/SiO2-6 has superior rate performance and lower impedance, because the carbon coating improves conductivity and kinetic performance. The method provides a strategy for integrated utilization of Si-rich biomass and preparation of C/SiO2 anode materials with desirable electrochemical properties.