多孔结构MnO_2电极材料的电容性能研究

Study on Capacitive Performance of Porous MnO_2 Electrode Materials

本文采用水热法制备了超级电容器用多孔结构MnO_2电极材料,以碳纳米纤维(CNF)为模板,通过400℃热处理去除材料中的CNF,得到多孔道结构MnO_2。利用X射线衍射(XRD)和扫描电子显微镜(SEM)对样品的结构和形貌进行表征,通过循环伏安曲线(CV)测试了样品在0.5 mol·L-1的Na2SO4溶液中的电容性能。结果表明,CNF均匀分布在MnO_2材料中,制备的MnO_2主要呈纳米棒状结构;热处理后,部分纳米棒结构转化为颗粒状结构,且添加的CNF量越高,转化生成的颗粒状物质越多,颗粒状物质主要为Mn2O3。制备的材料在0~0.8 V(vs SCE)电位范围内主要表现为赝电容行为,添加10 wt%的CNF热处理后制备的样品比电容值最高,达到202 F·g-1。

In this paper,porous MnO2 used for electrode materials of supercapacitors was prepared by hydrothermal method.Carbon nanofibers(CNF)were used as template,and then followed by heat treatment at 400℃to remove the CNF,and the porous structure of MnO2 was obtained.The structure and morphology of the samples were characterized by X-ray diffraction(XRD)and scanning electron microscope(SEM).The capacitance performances of the samples were tested in 0.5mol/L Na2SO4 solution by cyclic voltammetry(CV).The results showed that CNF was uniformly distributed in MnO2,and the prepared MnO2 was mainly appears in the shape of nanorod.After the heat treatment,the nanorods structure were partially transformed into granular structure,and the higher the CNF content,the more granular material was transformed and the granular materials were Mn2O3.The prepared materials were mainly showed in pseudocapacitive behavior in the potential range of 0~0.8V(vs SCE),and the highest specific capacitance value of the samples was reaching 202 F/g,which belonged to the sample who added 10 wt%CNF.