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 VO to take advantage of the selective growth of the (110) crystal plane of VO, facilitating sufficient diffusion of aniline within the VO interlayer along the vertical direction of the spatial c-axis while stabilizing the interlayer structure. The synthesized composite (PANI80-VO) 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-VO electrode exhibited an ultrahigh discharge capacity of 516.90 mAh g at a current density of 0.1 A g. Moreover, it exhibited a discharge capacity of 268.80 mAh g at a current density of 10 A g 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.