水热法制备3D rGO/Co_(3)O_(4-x)复合材料及超电容性能研究

Preparation of 3D rGO/Co_(3)O_(4-x)composite materials by hydrothermal method and its supercapacitor properties

利用一步水热合成法,以氧化石墨烯(GO)和六水合硝酸钴(Co(NO_(3))_(2)·6H_(2)O)为实验原料,简易制备了含氧空位的3D还原氧化石墨烯/四氧化三钴(3D rGO/Co_(3)O_(4-x))复合电极材料.通过扫描电镜、透射电镜观察,Co_(3)O_(4-x)呈线状或球状均匀分布在多孔网络结构的3D rGO上,表明了3D rGO/Co_(3)O_(4-x)复合材料的成功制备.在2 mV/s的扫描速率下,基于Co_(3)O_(4-x)质量比电容为635.7 F/g.将复合电极材料组装成对称型超级电容器,在功率密度为100 W/kg时,得到的能量密度为10.6 Wh/kg.经过10000次电化学循环后的电容保持率为98.15%.对称型超级电容器优异的电化学性能归因于石墨烯高的比表面积、良好的多孔性以及Co_(3)O_(4-x)与石墨烯之间的协同效应.

A three⁃dimensional reduced graphene oxide/cobaltosic oxide composite electrode material containing oxygen vacancies(3D rGO/Co_(3)O_(4-x))was simply prepared by one⁃step hydrothermal synthesis using graphene oxide(GO)and cobalt nitrate hexahydrate(Co(NO_(3))_(2)·6H_(2)O).The uniform distribution of linear and spherical⁃shaped Co_(3)O_(4-x)on the 3D rGO with porous network structure was displayed by scanning electron microscopy and transmission electron microscopy,indicating the successful preparation of the 3D rGO/Co_(3)O_(4-x)composite.At a scan rate of 2 mV/s,the specific capacitance based on Co_(3)O_(4-x)was 635.7 F/g.A symmetrical su⁃percapacitor was assembled using the composite electrode materials,which exhibited an energy density of 10.6 Wh/kg at a power den⁃sity of 100 W/kg.After 10000 cycles,the capacitance retention rate was as high as 98.15%.The excellent electrochemical perform⁃ance of the symmetrical supercapacitor was attributed to the high specific surface area,good porosity of graphene and the synergistic effect between Co_(3)O_(4-x)and graphene.