Rational design of hierarchical Si@T-Nb₂O₅ core-shell nanocomposites encapsulated in conductive carbon matrices for high-performance lithium-ion battery anodes

Silicon anodes for advanced lithium-ion batteries (LIBs) are promising due to intrinsic advantages including ultrahigh theoretical capacity (4200 mAh g −1 ), near-optimal Li + /Li potential (∼0.4 V), abundant availability and environmental benignity. However, practical application is hindered by severe intrinsic challenges: drastic volume expansion (>300%), unstable solid-electrolyte interphase (SEI) formation, and sluggish reaction kinetics. To address these limitations, we fabricated a novel Si@T-Nb₂O₅@Carbonized-coxial carbon nano fiber composite via a scalable hydrothermal-electrospinning approach, featuring silicon nanoparticles encapsulated in a nitrogen-doped porous carbon matrix with an engineered T-Nb₂O₅ interphase layer. Theoretical simulations demonstrate that the T-Nb₂O₅ interphase promotes Li + diffusion and reduces the energy barrier at carbon/Si interfaces. The optimized electrode exhibits excellent cycling stability and high-rate performance (1030.1 mAh g −1 after 100 cycles at 0.2 A g −1 ; 507.7 mAh g −1 after 500 cycles at 2.0 A g −1 ). Notably, flexible pouch cells maintain stable LED illumination under repeated mechanical deformation, indicating great practical potential. This integrated electrospinning strategy provides a scalable manufacturing platform for high-energy flexible batteries.