膨胀石墨/纳米氧化锌/锌复合电极材料的超级电容器性能

Preparation of exfoliated graphite/ZnO/Zn nanocomposite for supercapacitor applications

以膨胀石墨为原料,与滚压振动磨预处理得到的纳米锌粉混合,超声分散24h制备膨胀石墨-纳米氧化锌及锌的复合电极材料(EG/ZnO/Zn)。采用X射线衍射仪(XRD)、场发射扫描电子显微(SEM)、场发射透射电子显微镜(TEM)、拉曼光谱分析仪(Raman),对材料的微观结构及成分表征。结果表明,复合材料中含锌和氧化锌,纳米锌粉颗粒和氧化锌纳米棒在膨胀石墨表面和层间分散良好,其中氧化锌纳米棒呈现出六方晶系纤锌矿结构,其直径大约为20nm。利用电化学循环伏安和恒电流充放电对材料进行电化学电容性能测试,表明经处理的复合电极材料在0.1A/g的电流密度下有明显的赝电容特性,比电容达147F/g,其赝电容来源不只是欠电位沉积的化学吸附,还有氧化还原反应。

The nanocomposite material was synthesized by sonicating the dispersion of exfoliated graphite(EG) and Zinc nano-particles obtained by roller vibration milling at room temperature.The microstructure of the nanocomposite material(EG/ZnO/Zn) was studied with the X-ray diffraction(XRD),scanning electron microcopy(SEM),transmission electron microscopy(TEM) and Raman spectroscopy(Raman).The results reveal that the composite electrode material contains both Zn and ZnO,which grow on the surface and the interlayer of the exfoliated graphite equably.Rod-like nano ZnO is hexagonal wurtzite structure,about 20 nm in diameter.The capacitive performance of the nano composite is analyzed through cyclic voltammetry and chronopotentiometry tests.The results show sonicated exfoliated graphite; EG /ZnO/Zn composite,as compared with raw exfoliated graphite,exhibit an improved capacitance of 147 F/g with good charge/discharge behavior.While,both the chemisorption of underpotential deposition and the redox reaction compose the pseudocapacitance.