Engineering vanadium dioxide cathodes toward ultrastable zinc ion batteries

Rechargeable aqueous zinc-ion batteries (ZIBs) represent a promising energy storage technology due to their intrinsic safety, low cost, and environmental compatibility. However, the practical application of vanadium-based cathodes is hindered by structural instability and rapid capacity decay during cycling. Herein, we develop an Al 3+ doping strategy to engineer the VO 2 cathode with remarkably enhanced stability. The introduction of Al 3+ not only induces favorable oxygen vacancies but also reinforces the host structure, effectively mitigating lattice strain and minimizing vanadium dissolution. The resulting Al2-VO 2 cathode exhibits a high specific capacity of 452 mAh g −1 at 0.1 A g −1 and exceptional long-term cyclability, retaining ∼70% capacity after 10000 cycles at 10 A g −1 . Kinetics studies further reveal capacitive-dominated storage behavior and facilitated Zn 2+ diffusion, underscoring the role of defect engineering in boosting electrochemical performance. This work provides a feasible cation-doping approach to realize highly stable VO 2 -based cathodes for sustainable energy storage applications.