Oxygen-deficient ZnVOH@CC as high-capacity and stable cathode for aqueous zinc-ion batteries

Vanadium oxides have become promising cathodes for aqueous zinc ion batteries (AZIBs) due to their low cost and high theoretical capacity. However, vanadium oxides suffer from the problems of low electrical conductivity and structural instability. To address the challenges, ZnxV2O5 & sdot;nH2O x V 2 O 5 & sdot;nH 2 O with oxygen-rich vacancies was synthesized in situ on carbon cloth (ZnVOH@CC) via a one-step hydrothermal method. The introduction of Zn2+ 2 + and oxygen vacancies is beneficial to enhance the structural stability and improve the Zn2+ 2 + diffusion rate. The pre- intercalated Zn2+/H2O 2 + /H 2 O acts as "pillars" to increase the interlayer spacing of vanadium pentoxide (V2O5), 2 O 5 ), weakening the electrostatic interactions between Zn2+ 2 + and the ZnVOH host lattice. Benefiting from the above advantages, the ZnVOH@CC composite was used as the cathode for AZIBs, which showed a high capacity of 464.9 mAh/g at 0.1 A/g, a large capacity of 208.1 mAh/g at 1.0 A/g after 1,000 cycles, and a good cycling stability at a high current density of 5.0 A/g after 10,000 cycles. In addition, the assembled ZnVOH@CC//Cu2Se 2 Se full cell by matching ZnVOH@CC with Cu2Se 2 Se also exhibits a high reversible capacity of 68 mAh/g at 1.0 A/g and 92.5 % capacity retention after 260 cycles.