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Designing and synthesizing cathode materials with high specific capacity and stability for aqueous zinc ion battery remains a significant challenge. In this study, citric acid was selected as the reducing agent for converting V2O5 to VO2 with a carbon matrix using the hydrothermal method. The introduction of citric acid not only created a distinct microstructure in V4+ materials but also provided carbon matrix, which resulted in a fast diffusion of zinc ion and a good conductivity. This carbon containing vanadium-oxide material exhibited excellent electrochemical performance as a cathode material for aqueous zinc ion batteries, showing a high specific capacity of 399.33 mAh g−1 at 1 A g−1, and a capacity retention rate up to 98.3% after cycling for 1000 cycles at a high current density of 5 A g−1. [ABSTRACT FROM AUTHOR]

One of the hottest research topics at present is the construction of environmentally friendly and secure aqueous zinc-ion batteries (AZIBs) using an aqueous electrolyte instead of an organic electrolyte. As a result of their diverse structure, valence state, high theoretical specific capacity, and other benefits, vanadium-based materials, which are frequently employed as the cathode of AZIBs, have drawn the attention of many researchers. The low cycle stability of zinc ion batteries (ZIBs) is mostly caused by the disintegration of the vanadium-based cathode materials during continuous charge and discharge. In this work, using 3M Zn(CF3SO3)2 as the electrolyte and hydrothermally synthesized Ag2V4O11 as the cathode material, the high-rate performance and extended cycle life of ZIBs were evaluated. The effects of different hydrothermal temperatures on the microstructure, capacity, and cycle stability of the Ag2V4O11 cathode material were examined. The experimental results show that Ag2V4O11 exhibits a typical intercalation-displacement process when used as the cathode material. The multiplicative performance and cycle stability of the cathode material were significantly enhanced at a hydrothermal temperature of 180 °C. Ag2V4O11-180 has a high discharge specific capacity of 251.5 mAh·g−1 at a current density of 0.5 A·g−1 and a long cycle life (117.6 mAh·g−1 after 1000 cycles at a current density of 3 A·g−1). According to the electrochemical kinetic investigation, the cathode material has a high pseudocapacitive charge storage and Zn2+ diffusion coefficient. This is attributed to the large layer spacing and the Ag+ anchored interlayer structure. [ABSTRACT FROM AUTHOR]