RuO_2/石墨烯纳米复合材料的合成及其电化学性能

Synthesis of RuO_2/graphene nanocomposites and the electrochemical performance for supercapacitors

通过水热反应和高温焙烧方法制备了负载RuO_2纳米粒子的石墨烯纳米复合材料(RuO_2/G)。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、热重分析(TGA)和X射线光电子能谱(XPS)对材料的结构和形貌进行了表征。结果表明,在复合材料中,平均粒径为3.6nm的RuO_2纳米粒子均匀地负载在石墨烯片层上。该材料作为超级电容器的电极材料,表现出了良好的电容性能。当RuO_2的质量分数为35%时,在6mol/L KOH电解液中,复合材料的比电容为402.5F/g,且表现出了较高的能量密度(14 Wh/kg)和功率密度(50 W/kg)。该复合材料体现了石墨烯双电层电容和RuO_2赝电容的性质,为性能优异的储能材料。

RuO2/graphene （RuO2/G） composites were synthesized through a hydrothermal reaction and followed by an annealing process. The structure and morphology of the materials were characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM）, transmission electron microscopy （TEM）, thermogravimetric analysis （TGA） and X-ray photoelectron spectroscopy （XPS）. The results show that RuO2 nanoparticles with average size of 3.6 nm are homogeneously deposited on the surface of the graphene sheets. As an electrode mate rial, RuO2/G exhibits an excellent supercapacitive behavior. Electrochemical performance of the materials was evaluated by cyclic voltammetry （CV）, galvanostatic charge discharge and electrochemical impedance spectros-copy （EIS）. With 35wt% RuO2 loading, RuO2/G shows a specific capacitance of 402.5 F/g in 6 mol/L KOH electrolyte. Meanwhile, the electrode material also delivers a high energy density of 14 Wh/kg and power densi-ty of ,50 W/kg in aqueous electrolyte system. Moreover, the RuO2/G material exhibits good rate performance and cycle stability, utilizing the double layer capacitance of graphene and the pseudocapacitance of RuO2,RuO2/G composite is an ideal electrode material for the energy storage device.