Recycling of photovoltaic silicon and graphite waste to prepare three-dimensional silicon/artificial graphite/carbon anodes for lithium-ion battery

Abstract

The production of silicon (Si) wafers generates substantial amounts of micron-sized, high-purity Si waste, resulting in environmental pollution and resource loss. Similarly, the manufacturing of artificial graphite (AG) components results in the generation of significant amounts of unused AG waste. This research focuses on the development of a carbon (C) coated Si/AG composite material with long cycle stability by recycling Si and AG waste. Initially, purified Si waste is combined with anhydrous ethanol and processed in a sand mill to create a Si-containing nanoslurry. Next, carbon nanotubes, polyvinylpyrrolidone, and AG waste are incorporated into the SM-nano Si, mixed, and then spray-dried. The final step involves high-temperature annealing in a hydrogen-argon atmosphere to develop a three-dimensional interpenetrating Si/AG/C structure. When used as the anode material in lithium-ion batteries, the coin cell maintains a capacity of 639 mAh g⁻¹ after 500 cycles at a current density of 500 mA g⁻¹ , achieving a capacity retention rate of 88 %. Following additional electrostatic modification, the capacity rises to 691.7 mAh g⁻¹ . This study highlights the potential of recycling Si and AG waste to produce high-performance Si/C anode materials, significantly contributing to the sustainable reuse of discarded resources.