水相锌二次电池正极材料V2O5/C的电化学性能研究

采用溶胶－凝胶法合成了一种V₂O₅/C复合材料.扫描电镜（SEM）和红外光谱（FTIR）分析表明,这是一种外层V₂O₅胶体包覆内层乙炔分子的多孔复合材料.以V₂O₅/C作正极,锌片为负极,Zn(ClO₄)₂溶液为电解质组成水相锌二次电池,采用循环伏安（CV）和电化学阻抗谱（EIS）等方法研究发现:V₂O₅:C质量比为1:1时电极具有最好的电化学性能,电池开路电压达1.64 V; Zn^2＋能分别在1.01 V和1.26 V处分步嵌入V₂O₅/C结构中A、B两种位置,其嵌入电流密度峰值最高可达70 mA?g^－1,并且具有较好的循环充放电性能;在一定放电深度下,V₂O₅/C电极反应速率受Zn^2＋的扩散过程控制.

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.