Synergistic Phase and Structural Engineering for Enhanced Zinc Storage in V₂O₃@N-Doped Carbon Nanofibers

Vanadium-based oxide cathodes are promising energy-storage systems for aqueous zinc-ion batteries (AZIBs) because of their high energy density and safety, and low cost. However, their limited ion/electron transfer rates and rapid capacity decay pose challenges to their practical application. To overcome these limitations, V₂O₃ nanoparticles are developed with surface oxygen vacancies integrated with N-doped carbon nanofibers (V₂O₃@NCNFs), using an electrospinning method combined with an in situ oxidation/reduction strategy. By precisely controlling the reaction atmosphere, synergistic regulation of the phase transition and structural evolution of vanadium oxide are achieved. The unique combination of oxygen vacancies and N-doped carbon nanofibers enhances the zinc storage capacity, rate capability, and cycle stability of the V₂O₃@NCNFs electrode, achieving high reversible capacities of 554.6 mAh g^-1 at 0.1 A g^-1 with a high loading mass of ≈2.0-2.5 mg cm^-2. Moreover, the V₂O₃@NCNFs electrode can achieve a high initial capacity of 434.3 and 266.6 mAh g^-1 even at high current densities of 1.0 and 5.0 A g^-1, respectively, with minimal capacity decay rates of 0.012% per cycle over 500 cycles and 0.003% per cycle over 2000 cycles. More importantly, this innovative approach can be universally applied to the design of novel nanostructured Mn- and V-based oxide cathodes, which is promising for the development of advanced electrodes for high-performance energy storage devices.