Ammonium Vanadate Porous Nanobelts Modified with N-Doped Hollow Carbon Nanocubes for Highly Stable Aqueous Zinc-Ion Batteries under 15 A g ⁻¹

The practical deployment of aqueous zinc-ion batteries (AZIBs) for large-scale energy storage is severely hampered by the lack of high-performance cathode materials, which typically exhibit slow Zn 2+ diffusion kinetics and structural degradation and thus cause rapid capacity decay. Here we show that both kinetic and structural limitations can be addressed by engineering a composite of NH 4 V 4 O 10 (NVO) porous nanobelts in situ integrated with N-doped hollow carbon nanocubes (NC). The porous framework facilitates ionic diffusion, while the incorporated NC network enhances electronic conductivity and provides a mechanical buffer that preserves structural integrity. DFT calculations reveal strong electronic interaction at the NVO@NC interface and a substantially lowered Zn 2+ migration barrier, confirming that the NC framework promotes charge transfer and ion diffusion. The NH 4 + pillars stabilize the layered structure, enabling a rapid and reversible H + /Zn 2+ co-intercalation process that facilitates fast Zn 2+ transport. Consequently, the optimized NVO@NC-30 cathode delivers a high capacity of 453.1 mAh g −1 at 0.5 A g −1 and retains 227.5 mAh g −1 even at a high rate of 15 A g −1 . Moreover, it exhibits excellent long-term cycling stability at 15 A g −1, retaining 85.6% of its initial capacity after 10,000 cycles. The study demonstrates that integrating a conductive carbon framework with buffering capacity is an effective strategy to enhance the rate capability and mitigate structural instability of vanadium-based cathodes.