Manufacturing lithium-ion anodes from silicon recovered from end-of-life solar panels

[Display omitted] •Recycled photovoltaic silicon was surface-modified to synthesize amorphous carbon and carbon nanotubes, resulting in a double carbon layer that mitigates the lithiation expansion of silicon. Additionally, a durable and stable solid electrolyte layer was formed using lithium difluoro-oxalate borate. With the rapid growth of solar energy, the recycling or re-use of used solar panels has become a key issue. Recycling high-value photovoltaic silicon from solar cells is an important step towards achieving “carbon neutrality.” In this paper, an efficient and high-value recycling strategy is employed to convert recycled silicon from discarded solar cells into lithium-ion anode materials. In this case, the recycled PV silicon is etched with hydrofluoric acid (HF) to create a porous silicon structure. This structure is designed to withstand the expansion stress of the electrodes. After surface modification with citric acid and carbon nanotubes to enhance the electrical conductivity of the recycled silicon and buffer the electrode from stress expansion during lithium storage and release, lithium difluorooxalate borate was added to pre-treat the surface of the recycled photovoltaic silicon through heat treatment. This process creates a robust and fast lithium-ion conductive interface enriched with LiF, Li2C2O4, LiBO2, and Li2B4O7. Density Functional Theory (DFT) calculations were performed to investigate the electronic structure of the synthesized materials, revealing their remarkable electronic conductivity and atomic bonding characteristics. When used as an anode for Li-ion batteries, W-pSi@C/CNTs exhibited high initial coulombic efficiency with stable cycling, demonstrating a capacity of 2040 mAh/g at 0.2 A/g for 200 cycles. In addition, this high-value recycling will help promote the development of renewable energy in an economically and environmentally sustainable manner.