Molten salt electrolysis upcycling of silica tailings into functional NiSi2/SiNWs: A clean and sustainable approach for high-value industrial waste reclamation

In this study, we utilized the intrinsic small particle size and crystalline structure of silica tailings to synthesize NiSi 2 /SiNWs composites via a NiO-catalyzed, energy-efficient, and environmentally friendly molten salt electrochemical method. Metallic silicide droplets exhibited in-situ formation and dynamic migration. This dual-process mechanism simultaneously guided silicon nanowire growth and established conductive networks. The NiSi 2 /SiNWs electrode demonstrated enhanced crack resistance and optimized diffusion kinetics, achieving an initial Coulombic efficiency of 90.7 %. It maintained a reversible capacity of 500.6 mAh g −1 after 350 cycles. Rate capability tests showed that its capacity rapidly recovered to 86 % of its initial value. In addition, Galvanostatic intermittent titration technique (GITT) was employed to evaluate the enhanced Li + transport kinetics and electrochemical reactivity of NiSi 2 /SiNWs composites. This work presents an energy-efficient approach for engineering silicon-based anodes, simultaneously achieving sustainable silica tailings upcycling and establishing a cost-effective silicon sourcing paradigm with dual environmental and technological benefits.