Quench-tailored Al-doped V2O5 nanomaterials for efficient aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) are regarded as a promising competition to lithium-ion batteries as energy storage devices, owing to their high safety and low cost. However, the development of high-performance ZIBs is largely hindered by the shortage of ideal cathode materials with high-rate capability and long-cycle stability. Herein, we address this bottleneck issue by the quenching-tailored surface chemistry of V2O5 cathode nanomaterial. By rapid quenching from high temperatures, Al ions are doped into V2O5 lattice (Al-V2O5) and abundant oxygen vacancies are formed on the surface/near-surface, which facilitate the desired rapid electron transfers. Our density functional theory (DFT) simulations elucidate that the doping of Al ions into V2O5 remarkably reduces the Zn2+-diffusion barriers and improves the electrical conductivity of V2O5. As a proof-of-concept application, the thus-optimized Al-V2O5 cathode delivers a superior specific capacity of 532 mAh g−1 at 0.1 A g−1 and a long-cycling life with 76% capacity retention after 5000 cycles, as well as a good rate performance. This work provides not only a novel strategy for tuning the surface chemistry of V2O5 to boost the Zn2+ storage but also a general pathway of modifying metal oxides with improved electrochemical performance.