Microsized Porous SiO@C Composites Synthesized through Aluminothermic Reduction from Rice Husks and Used as Anode for Lithium-Ion Batteries.

Microsized porous SiO@C composites used as anode for lithium-ion batteries (LIBs) are synthesized from rice husks (RHs) through low-temperature (700 °C) aluminothermic reduction. The resulting SiO@C composite shows mesoporous irregular particle morphology with a high specific surface area of 597.06 m/g under the optimized reduction time. This porous SiO@C composite is constructed by SiO nanoparticles uniformly dispersed in the C matrix. When tested as anode material for LIBs, it displays considerable specific capacity (1230 mAh/g at a current density of 0.1 A/g) and excellent cyclic stability with capacity fading of less than 0.5% after 200 cycles at 0.8 A/g. The dramatic volume change for the Si anode during lithium-ion (Li) insertion and extraction can be successfully buffered because of the formation of LiO and LiSiO during initial lithiation process and carbon coating layer on the surface of SiO. The porous structure could also mitigate the volume change and mechanical strains and shorten the Li diffusion path length. These characteristics improve the cyclic stability of the electrode. This low-cost and environment-friendly SiO@C composite anode material exhibits great potential as an alternative for traditional graphite anodes.