Defective construction of vanadium-based cathode materials for high-rate long-cycle aqueous zinc ion batteries

The development of structurally stable, highly conductive layered materials as cathode materials for aqueous zinc-ion batteries (AZIBs) is essential. Herein, polyaniline (PANI) was inserted into the interlayer of a vanadium-metal-organic framework-derived V₂O₅ to take advantage of the selective growth of the (110) crystal plane of V₂O₅, facilitating sufficient diffusion of aniline within the V₂O₅ interlayer along the vertical direction of the spatial c-axis while stabilizing the interlayer structure. The synthesized composite (PANI80-V₂O₅) exhibited excellent electrochemical properties owing to the increase in the material layer spacing from 5.76 Å to 14.31 Å and the strong synergistic effect of the oxygen vacancies and large specific surface area of the material. In addition, the π-conjugated structure of PANI prevented the active material from dissolving in the electrolyte, further stabilizing its lamellar structure, which tended to collapse during electrochemical cycling. The PANI80-V₂O₅ electrode exhibited an ultrahigh discharge capacity of 516.90 mAh g^-1 at a current density of 0.1 A g^-1. Moreover, it exhibited a discharge capacity of 268.80 mAh g^-1 at a current density of 10 A g^-1 and a capacity retention rate of 97.77% after 3000 cycles. Therefore, this study provided a reference for developing structurally superior cathode materials for AZIBs.