Hydrogen Peroxide Tuned Morphology and Crystal Structure of Barium Vanadate-Based Nanostructures for Aqueous Zinc-Ion...

Improving the layered-structure stability and suppressing vanadium (V) dissolution during repeated Zn²⁺ insertion/extraction processes are key to promoting the electrochemical stability of V-based cathodes for aqueous zinc (Zn)-ion batteries (AZIBs). In this study, barium vanadate (Ba₂V₂O₇, BVO) nanostructures (NSs) are synthesized using a facile hydrothermal method. The formation process of the BVO NSs is controlled by adjusting the concentration of hydrogen peroxide (H₂O₂), and these NSs are employed as potential cathode materials for AZIBs. As the H₂O₂ content increases, the corresponding electrochemical properties demonstrate a discernible parabolic trend, with an initial increase, followed by a subsequent decrease. Benefiting from the effect of H₂O₂ concentration, the optimized BVO electrode with 20 mL H₂O₂ delivers a specific capacity of 180.15 mA h g^-1 at 1 A g^-1 with good rate capability and a long-term cyclability of 158.34 mA h g^-1 at 3 A g^-1 over 2000 cycles. Thus, this study provides a method for designing cathode materials with robust structures to boost the electrochemical performance of AZIBs.