Upcycling of photovoltaic silicon waste into Si/Cu@GLC anodes for lithium-ion batteries

Silicon anodes are promising candidates for next-generation lithium-ion batteries owing to their high theoretical capacity. However, the practical application of silicon anodes is limited by severe volume expansion and poor cycling stability. This study presents a sustainable and cost-effective strategy for synthesizing high-performance graphene-like carbon (GLC)-coated silicon/nano‑copper (Si/Cu@GLC) composites using photovoltaic silicon cutting waste (SCW) as the starting material. The synthesis combines copper-assisted chemical etching with the catalytic pyrolysis of humic acid, yielding a composite with enhanced electrochemical performance. Economic and environmental assessments reveal that the SCW-derived Si/Cu@GLC exhibits lower production costs and CO₂ emissions than conventional silicon anode fabrication processes. The Si/Cu@GLC composite exhibits a high initial discharge capacity of 2333.98 mAh g ⁻¹, along with excellent cycling stability and superior rate capability. The GLC coating and nanoporous structure synergistically mitigate volume expansion, resulting in a low expansion rate of only 157 % after 100 cycles. Upon integration into a full cell with an LFP (Lithium Iron Phosphate) cathode, Si/Cu@GLC exhibits excellent cycling stability, retaining 86.7 % of its capacity after 200 cycles at 0.5C. This study provides a sustainable and scalable approach for upcycling photovoltaic silicon waste into high-performance silicon–carbon anodes. The findings highlight the potential of an eco-friendly circular production model that combines economic viability with superior battery performance.