Hybrid Anodes with Enhanced Lithium-Ion Diffusion by In Situ Interfacial Engineering between Photovoltaic Silicon Waste and Bamboo Fiber-Derived Carbon

Abstract The practical application of silicon-based anodes is primarily limited by their substantial volume expansion (300–400%) during repeated lithiation/delithiation cycling and inherently low electrical conductivity, leading to challenges such as particle pulverization, unstable solid electrolyte interphase (SEI), sluggish ion diffusion, and rapid capacity fading. To address these issues, a hybrid anode (Si@BCF@Camor) with upcycled photovoltaic waste silicon and bamboo-derived carbon fibers (BCF) was developed using an innovative polymerization–reaction coating interface engineering strategy. This approach involves constructing a 3D conductive scaffold through electrostatic assembly between functionalized nanosilicon and BCF, followed by coating the frameworks with a defect-rich amorphous carbon layer via in situ polymerization and carbonization along with reactions occurring between citric acid and ethylene glycol. The in situ-built dual-carbon structure accommodates volume changes and suppresses aggregation, while the optimized Si@BCF@Camor hybrid anode exhibits enhanced ionic transportation kinetics and stability along with low charge-transfer resistance (52.46 Ω), a high Li+ diffusion coefficient (10–9.72–10–12.29 cm2 s–1), high initial Coulombic efficiency (82.7%), and excellent rate performance (1048.2 mAh g–1 after 200 cycles at 0.1 A g–1). This work offers a sustainable and efficient strategy for overcoming interfacial and kinetic limitations in silicon-based anodes.