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 V 2 O 5 to take advantage of the selective growth of the (1   1   0) crystal plane of V 2 O 5 , facilitating sufficient diffusion of aniline within the V 2 O 5 interlayer along the vertical direction of the spatial c -axis while stabilizing the interlayer structure. The synthesized composite (PANI80-V 2 O 5 ) 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-V 2 O 5 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.