Green synthesis of high-performance porous carbon coated silicon composite anode for lithium storage based on recycled silicon kerf waste

The effective management of silicon kerf waste produced from silicon wafer cutting processes of photovoltaic industry is of great significance for environmental protection and resources recycle. High-purity silicon kerf waste collected by acid-assisted separation and purification can be recycled as silicon source of silicon-based anode for lithium storage. Although volume volatility and low conductivity rooted in silicon anode are effectively handled by constructing carbon coated silicon composite with porous structure, it is always impeded by a HF-involved synthesis process for etching SiO2 as template. Here, a green systhesis approach for porous carbon encapsulated recycled silicon kerf waste (Si@PC) are reasonably designed that calcium carbonate (CaCO3) constructed as sacrificial layer is effortlessly removed away by HCl-assisted pickling, leaving porous structure. When evaluated in LIBs, the discharge capacity keeps at 712.6 mAhg−1 after 200th cycle at 0.5 Ag−1, whose initial capacity reaches to 2739.2 mAhg−1; Meanwhile, it demonstrates a significantly improved rate performance. In brief, this work provides a green and low-cost method to synthesize high-performance silicon/carbon composite with porous structure as anode for lithium storage based on recycled silicon kerf waste, meanwhile offers a new viewpoint for the effective management of silicon kerf waste from photovoltaic industry with high value.