石墨烯包覆分子筛复合电极材料的制备及其性能研究

以4A分子筛(4A)和改进Hummers法制备的氧化石墨烯凝胶(GO)为原料, 按一定质量比进行混合超声分散, 以混合分散液为前驱体煅烧制备了氧化还原石墨烯(RGO)包覆的三维复合4A/RGO电极材料。采用X射线衍射(XRD)、拉曼光谱(Raman)、孔径分析、扫描电子显微镜(SEM)和电化学测试等方法研究了复合材料的结构、形貌及超级电容性能。测试结果表明, 4A均匀地穿插在RGO片层中, 阻止了RGO片层之间相互堆积, 而RGO片层之间相互链接, 形成三维空间导电网络, 提高了复合电极材料的导电性。当GO与4A质量比为1:6时, 复合材料在4 A/g电流密度下比电容可达450 F/g, 在此电流密度下循环800次后, 其比容量保持率为85.7%, 表现出良好的倍率性能和循环稳定性。该4A/RGO复合电极材料超级电容性能优于纯4A或RGO, 可归因于4A和RGO之间的协同效应。

Preparation and Electrochemical Performance of Composite Electrode Material of Molecular Sieve Coated with Graphene

A 3D composite electrode was prepared by ultrasonic dispersion of a suspension mixed proportionally with 4A molecular sieve (4A) and graphene oxide gel (GO). The structure, morphology and electrochemical property of the 4A/reduced graphene oxide (RGO) composite were investigated by X-ray diffraction, Raman spectra, pore analysis, scanning electron microscope (SEM) and electrochemical measurements. The result shows that 4A is firmly adhered on the surface of RGO sheets, which can effectively avoid the stacking of RGO sheets. The RGO sheets link with each other to form a 3D electric conductive network in which can increase the electrical conductivity of the composite. The specific capacitance of 4A/RGO composite can reach 450 F/g at current density of 4 A/g when the mass ratio of graphene oxide and 4A is 1:6. Furthermore, the specific capacitance of 4A/RGO remains at 85.7% after 800 cycles under the same current density. Therefore these results indicate that this new composite possesses good rate capability and cycle stability and its supercapacitive performance is better than that of pure RGO or 4A. The excellent performance of the 4A/RGO composite can be attributed to the synergy between RGO and 4A.