电沉积法制备石墨烯/MnO_2纳米复合电极的电容性能  

Capacitive properties of graphene/MnO_2 nano-composite electrode synthesized by electrodeposition

作　　者：邓高 何捍卫[1] DENG Gao;HE Hanwei(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2018年第4期398-406,共9页Materials Science and Engineering of Powder Metallurgy

摘　　要：采用循环伏安法,先在泡沫镍基体上沉积多孔结构的MnO_2纳米片,然后再沉积一层还原石墨烯,得到石墨烯/MnO_2复合材料。采用扫描电镜(SEM)、X射线衍射仪(XRD)与X射线光电子能谱仪(XPS)分析该材料的形貌、结构与价态。采用循环伏安、恒流充放电和电化学交流阻抗技术测试材料的比电容、循环稳定性和阻抗。结果表明,MnO_2为纳米片状结构,石墨烯基本覆盖了MnO_2沉积层。MnO_2与石墨烯复合后,等效串联电阻由0.83Ω减小到0.4Ω,电荷转移电阻由9.34Ω下降到6.76Ω。在2 A/g充放电电流密度下,石墨烯/MnO_2复合电极的比电容为501 F/g,比MnO_2增大25%,在充放电循环3 000次后电容保持率为84%。The electrode graphene/MnO2 nano-composites were obtained by depositing a layer of reduced graphene on the porous MnO2 nanoscale which was deposited firstly on the foamed nickel substrate by cyclic voltammetry.The morphology,phase and valence state of the material were analyzed by SEM,XRD and XPS.The specific capacitance,cyclic stability and resistance were characterized by the means of cyclic voltammogram,galvanostatic charge/discharge and electrochemical impedance spectrum.The results show that the MnO2 nanosheets are mostly coated by graphene.The equivalent series resistance and charge transfer resistance decrease form 0.83Ω,9.34Ωto 0.4Ω,6.76Ω,respeactivly.The specific capacitance of graphene/MnO2 composites at current density of 2 A/g is 501 F/g which has improved 25%compared to bare MnO2,and exhibit an 84%specific capacitance retention after 3 000 cycles.

关 键 词：超级电容器 电沉积 MNO2 石墨烯 纳米结构 复合电极 

分 类 号：TM532[电气工程—电器]