Silicophilic Interface-Induced Deposition and Surface Oxidation Enable High-Rate Nano-Confined Silicon/Carbon Anodes

Nano-confined silicon/carbon (Si/C) composites synthesized via chemical vapor deposition (CVD) hold great promise as high-capacity anodes for lithium-ion batteries, but their rate capability and cycling stability are severely undermined by micropore blockage, poor Si/C interfacial affinity, and low ionic conductivity of the SiC interphase. Herein, we report a synergistic strategy that integrates silicophilic interface-induced deposition with surface oxidation modification. Using ordered mesoporous carbon CMK3 enriched with N/O functional groups (CMK3@NO) as the scaffold, we fabricate CMK3@NO-Si@SiO2 composites through CVD followed by controlled oxidation. In this architecture, the N/O-rich silicophilic interface ensures uniform and dense silicon filling within the mesopores, while subsequent controlled oxidation partially converts the outer silicon layer into SiO2, which upon lithiation transforms in situ into a LixSiOy protective phase featuring high Li+ conductivity and superior mechanical toughness. This design yields three synergistic benefits: a mesoporous scaffold enabling rapid ion/electron transport, a silicophilic interface securing atomic-scale Si/C contact, and a LixSiOy layer facilitating fast interfacial Li+ migration while providing mechanical buffering. As a result, the CMK3@NO-Si@SiO2 anode delivers a reversible capacity of 805 mAh g-1 at 5 A g-1 and retains 81% of its capacity after 600 cycles at 2 A g-1. A full cell paired with LiFePO4 maintains 75% capacity retention after 200 cycles at 1 C. This work offers a paradigm for designing high-rate Si/C anodes through the synergistic engineering of interface chemistry and pore architecture.