Electrochemical properties of a V₂O₅/C composite in aqueous solution used for zinc secondary battery

A composite of vanadium pentoxide/carbon was prepared by sol-gel method. By using scanning electronic microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), it was found that the composite was composed of porous particles. Inner part of the composite was carbon particles which covered by an outer layer of vanadium pentoxide sol. The electrochemical properties of the composite as cathode material in aqueous solution for zinc secondary battery were studied by using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). When the mass ratio of V₂O₅/C was 1:1, the composite electrode showed good electrochemical properties: open circuit potential of its battery reached 1.64 V; zinc ions were reversibly intercalated into the composite electrode in site A at 1.26 V and site B at 1.01 V, with a highest intercalation rate 70 mA·g^-1; cycling performance of the composite electrode was quite good in a test of 20 charge-discharge cycles. The reaction process of V₂O₅/C composite electrode was controlled by the diffusion rate of zinc ions in V₂O₅.