Regeneration of photovoltaic industry silicon waste toward high-performance lithium-ion battery anode

The diamond-wire sawing silicon waste (DWSSW) from the photovoltaic industry has been widely considered as a low-cost raw material for lithium-ion battery silicon-based electrode, but the effect mechanism of impurities presents in DWSSW on lithium storage performance is still not well understood; meanwhile, it is urgent to develop a strategy for changing DWSSW particles into high-performance electrode materials. In this work, the occurrence state of impurities presents in DWSSW was carefully analyzed using in situ Ar ion etching technology. Then, the novel Si@C@SiO_x@PAl-N–C composite was designed through in situ encapsulation strategy. The obtained Si@C@SiO_x@PAl-N–C electrode shows a high first capacity of 2343.4 mAh·g⁻¹ with an initial Coulombic efficiency (ICE) of 84.4% under current density of 1.0 A·g⁻¹, and can deliver an impressive capacity of 984.9 mAh·g⁻¹ after 200 cycles. Combined numerical simulation modeling calculations, the increase in proportion of Si⁴⁺/Si⁰ and Si³⁺/Si⁰ valence states in SiO_x layer leads to a decrease in von Mises stress, which ultimately improves the cycling structural stability. Meanwhile, the porous 2D–3D aluminum/nitrogen (Al/N) co-doped carbon layer and nanowires on SiO_x layer can provide abundant active sites for lithium storage due to its developed hierarchical pores structure, which facilitates ion transport. What is more, the performance of Si@C@SiO_x@PAl-N–C//LiFePO₄ full cell shows its great potential in practical application. Graphical abstract: (Figure presented.)