Scalable Synthesis of a Si/C Composite Derived from Photovoltaic Silicon Kerf Waste toward Anodes for High-Performance Lithium-Ion Batteries

The solid waste from solar photovoltaic (PV) systems diverges from carbon neutrality targets and the core principles of clean energy. Herein, we present an innovative and cost-effective strategy to fabricate P-SKW@C as anode materials based on the natural properties of submicron silicon kerf waste (SKW) by increasing the surface oxide layer and combining the synergistic effects of magnesium thermal and acid leaching. In particular, the carbon layer establishes channels for electron and ion transport, thereby enhancing the conductivity of P-SKW@C and the mobility of lithium ions. The formation of pores by the synergistic effects of magnesium thermal and acid leaching provides buffer space to accommodate the volume changes in silicon, ensuring the structural integrity of the electrode. Specifically, the P-SKW@C anode exhibits superior rate performance, reaching 1006 mAh g^–1 at 2 A g^–1, and an outstanding reversible capacity of 1103 mAh g^–1 with the current density returning to 0.2 A g^–1. Furthermore, the P-SKW@C anode demonstrates a remarkable specific capacity of 905 mAh g^–1 at 500 mA g^–1 over 200 cycles. Notably, the assembled LiFePO₄//P-SKW@C full cell maintains a stable capacity of 105.96 mAh g^–1 and an energy density of 329.84 Wh kg^–1 at 0.5 °C after 50 cycles. This work introduces a new strategy for recycling the SKW in a sustainable, economical, and environmentally friendly way, facilitating the integration of solid waste and energy storage.