Synergistic nano-amorphization engineering enabled core-shell orthorhombic Nb2O5 nanofibers for high-rate and robust lithium storage

Orthorhombic Nb 2 O 5 (T-Nb 2 O 5 ) has emerged as a promising fast-charging anode due to its open framework structure, safe potential and intercalation pseudocapacitance characteristic. However, its practical application is hindered by the low electronic conductivity. Herein, a synergistic nano-amorphization engineering strategy was employed to fabricate crystalline-amorphous core-shell T-Nb 2 O 5 (C/A-T-Nb 2 O 5 ) nanofibers via electrospinning technology. The obtained carbon-free, chain-like C/A-T-Nb 2 O 5 nanofibers formed via interconnected Nb 2 O 5 nanoparticles enables rapid kinetics and excellent structural stability without compromising the energy density. The chemical etching creates an amorphous shell on single-crystalline core, which establishes a built-in electric field (BIEF) at the interface. In-situ characterizations with theoretical simulations suggest that BIEF effectively drives electrons from amorphous shell to the inner reaction sites and lowers Li-ions diffusion barrier. The amorphous shell with oxygen vacancies boosts Li-ions/electron transport, simultaneously alleviating lattice stress during cycling. Consequently, C/A-T-Nb 2 O 5 delivers a superior rate capability of 102 mAh g −1 at 50C and exceptional durability, retaining 69.5% capacity after 2000 cycles at 10C. A full pouch cell paired with C/A-T-Nb 2 O 5 anode and NCM811 cathode further demonstrates the practical viability. This integrated architectural modulation and amorphization engineering strategy establish a new paradigm for designing kinetically balanced electrodes for high-power batteries.