Plasma-enhanced vacancy engineering for sustainable high-performance recycled silicon in lithium-ion batteries

Silicon, renowned for its exceptional theoretical capacity, is a promising lithium-ion battery (LIB) anode material, yet its practical application is hindered by severe lithiation-induced volume expansion, structural instability, and high production costs. This study introduces a sustainable strategy to address these challenges by repurposing recycled photovoltaic (PV) silicon through a plasma-assisted vacancy engineering approach. By combining dielectric barrier discharge plasma-assisted milling with bismuth (Bi) modification, controlled vacancy defects are introduced into silicon microparticles, enhancing ion transport and mitigating internal stress. Bi further stabilizes the anode by absorbing mechanical stress and facilitating lithium-ion accommodation at vacancy sites. The resulting plasma induced silicon/carbon/bismuth composite demonstrates outstanding cycling stability and high-rate performance, retaining 1442 mA h g⁻¹ after 300 cycles at 0.5 A g⁻¹ and 525 mA h g⁻¹ after 1000 cycles at 7 A g⁻¹. This scalable and eco-friendly method not only overcomes the inherent limitations of silicon anodes but also transforms PV waste into high-performance LIB materials, advancing sustainable energy storage technologies.