Silicon@Carbon Composite with Bioinspired Root-Nodule Nanostructures as Anode for High-Performance Lithium-Ion Batteries

Silicon (Si) is a promising high-capacity anode material for lithium-ion batteries but faces challenges such as severe volume fluctuations during cycles and the formation of unstable solid-electrolyte interphase films on the electrode surface. To address these limitations, we developed a bioinspired Si@C composite anode through polydopamine-mediated self-assembly of aromatic polyamide nanofibers and nano-Si, followed by controlled pyrolysis at 1000 °C under N₂. The resulting hierarchical architecture mimics the symbiotic root-nodule structure of legumes, featuring vascular bundle-like carbon frameworks and chemically bonded Si/C interfaces. The optimized composite delivers an initial capacity of 1107.0 mAh g^-1 at 0.1 A g^-1 and retains 580.0 mAh g^-1 after 100 cycles with 52.4% retention. The exceptional electrochemical properties arise from the optimized architecture and surface interactions. The nature-inspired carbon network minimizes ionic transport resistance via vertically aligned porous pathways while simultaneously boosting lithium-ion adsorption capacity. Furthermore, radially aligned graphitic ribbons are generated through controlled polyamide thermal transformation that effectively mitigates electrode swelling and maintains stable interfacial layers during cycling.