Facile morphological construction of VO₂ and its application in aqueous Zn-ion batteries

Three distinct morphologies of VO2, namely flake-shaped VO2 (VO2(PIAN)), disc-shaped VO2 (VO2(BING)) and rod-shaped VO2 (VO2(BANG)) were synthesized using a facile one-pot hydrothermal method. As a cathode for aqueous zinc-ion batteries (AZIBs), the VO2(PIAN) demonstrates relatively superior electrochemical performance for aqueous zinc storage, including the high discharge specific capacity and long cycle life. After 500 cycles at a current density of 1000 mA/g, it retains a discharge capacity of 208.83 mA h/g, with a Coulombic efficiency nearing 100%, which can be attributed to the larger specific surface area and shortened Zn(2+ )diffusion distance, promoting faster electric transfer and Zn(2+ )diffusion kinetics. This work broadens the understanding of the electrochemical behavior of VO2-based AZIBs.