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

Abstract 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 Si 4+ /Si 0 and Si 3+ /Si 0 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//LiFePO 4 full cell shows its great potential in practical application.