Porous structure ZnV2O4/C-N composite activating vanadium-based cathode in aqueous zinc-ion batteries

Abstract

Constructing a loose structure by in-situ structural transformation can unlock the electrochemical activity of electrode materials. The porous ZnV2O4 particles coated with nitrogen-doped carbon (ZnV2O4/C-N composite) were synthesized by pyrolysis method. The electrochemical performance of ZnV2O4/C-N porous particles as cathode materials for ZIBs was studied. Undergoing electrochemical activation, discharge specific capacities of 301 mA h g−1 and 207 mA h g-1 can be obtained at the current density of 300 mA g-1 and 500 mA g−1, respectively. At a high current density of 2 A g-1, the ZnV2O4/C-N displays initial discharge specific capacity of 95 mA h g−1 and a maximum capacity of 147 mA h g −1. Additionally, the electrochemical behavior and mechanism of ZnV2O4/C-N were investigated. The pyrolysis process guides the in-situ formation of porous structure and the coating of nitrogen-doped carbon, which improves the activity of vanadium-based cathode and enhances the dynamic performance of ion diffusion. Thus, the reversible insertion and extraction of zinc-ions are ensured. The ZnV2O4/C-N exhibits higher electrochemical activity and improved electrochemical performance compared to its contrast.