Cost-effective preparation of high-performance Si@C anode for lithium-ion batteries

Silicon holds great potential as anode material for next-generation advanced lithium-ion batteries (LIBs) due to its exceptional capacity. However, its low conductivity and huge volume changes during charge/discharge process result in a poor electrochemical performance of silicon anode. This study introduces a cost-effective strategy to repurpose KL Si waste from photovoltaic industry into feedstock for LIBs. A Si@C composite with core–shell structure was synthesized from kerf loss (KL) Si waste as the primary capacity contributing ingredient. The nanoscale Si particles (Si NPs) was produced through ball milling and acid pickling of KL Si waste, and then coated a carbon shell by the pyrolyzed phenolic resin. This core–shell structure enhances the electrical conductivity of silicon-based anode, facilitates ion/electron movement, and reduces volume fluctuations of silicon during lithiation/de-lithiation process. Compared to the pure Si anode, the Li⁺ transmission efficiency of the Si@C anode was significantly improved, leading to a better cycle and rate performance. The resulting SP-2 electrode demonstrated a consistent capacity of 602 mAh g⁻¹ after 150 cycles under current density of 0.5 A g⁻¹.