Recycling silicon-based industrial waste as sustainable sources of Si/SiO2 composites for high-performance Li-ion battery anodes

Abstract Silicon-based materials (e.g., silicon and quartz) are widely utilized resources for industrial production. Despite the massive amount of annual consumption worldwide, recycling of silicon-based industrial waste toward high-value applications remains unsuccessful. In this work, Si/SiO2 composites are derived from silicon keff loss slurry in solar industry and quartz sand waste, and used for Li-ion battery anodes. By inheriting the intrinsic advantage of Si and SiO2 (i.e., high capacity and cycling stability, respectively), the composites exhibit 992.8 mAh g−1 after 400 cycles at 0.5 A g−1 with hardly any capacity decay. A controllable prelithiation method is further applied to the Si/SiO2 composites to compensate the irreversible capacity loss in the first cycle, resulting in an improved initial coulombic efficiency up to >90%. When paired with LiCoO2, the superior electrochemical performance of prelithiated Si/SiO2 composites enables a higher energy density (459.4 Wh kg−1) of the full cell than using commercial graphite anodes. This process demonstrates that silicon-based industrial waste can be cost-effective resources for high-performance Li-ion battery anodes through a simple, scalable and energy-efficient route.