Cu doped VO2 cathode materials for ultra-stable and high-performance aqueous zinc-ion batteries

Vanadium-based materials are considered to be the most promising cathode materials for aqueous zinc-ion batteries. Unfortunately, the existence of electrostatic forces between vanadium-based materials materials and zinc ions, as well as their poor intrinsic electrical conductivity and unstable structure, have further hindered the development of vanadium-based materials. Hence, a lamellar nanoflower-structured Cu0.05VO2 cathode material is prepared by Cu doped VO2 in the tunnel to improve its electrical conductivity and weaken the electrostatic repulsion force between it and zinc ions. The Cu0.05VO2 cathode can deliver a high capacity of up to 416 mAh g-1 at 0.5 A g-1 and maintain a capacity retention rate of 95.4 % after 6000 cycles at 10 A g-1. Experimental and theoretical calculations show that both the electrical conductivity and the zinc ion transport rate are greatly enhanced in Cu0.05VO2. Therefore, the Cu0.05VO2 cathode material shows potential for use in AZIBs.