Zincothermic-Reduction-Enabled Harvesting of an Si/C Composite from Rice Husks for a Li-Ion Battery Anode

Harvesting Si-based anode materials from environmentally friendly and abundant Si-containing natural resources not only meets the needs of the constantly widening Li-ion battery (LIB) markets but also promotes the utilization of agricultural waste. Herein, we report the fabrication of an Si/C composite derived from rice husks (RHs) via a low-temperature AlCl3-assisted zincothermic reduction. Thermodynamically, the bio-SiO2 blended with a carbon matrix is first transformed to SiCl4 and then reduced by Zn powder to produce Si nanoparticles. Due to the internal contact of bio-Si and C derived from RHs, the prepared Si/C composite displays an outstanding electrochemical performance; a capacity of 1033 mAh g–1 can be achieved over 100 cycles under 1 A g–1 with 6.6% capacity loss. What is more, the capacity of the Si/C composite can be maintained at 745 mAh g–1 over 250 cycles under 2 A g–1. In this work, a novel approach is developed to synthesize Si/C composites with the utilization of sustainable biomass resources for LIB anodes, enabling a high-value-added conversion for Si-based agricultural waste.