Rapid hydrothermal synthesis of hierarchical nanostructures assembled from ultrathin birnessite-type MnO2 nanosheets for supercapacitor applications
Rapid hydrothermal synthesis of hierarchical nanostructures assembled from ultrathin birnessite-type MnO2 nanosheets for supercapacitor applications
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DOI：
10.1016/j.electacta.2012.11.089
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发表时间：
2013-02
影响因子：
6.6
通讯作者：
Xiong Zhang;Pengmei Yu;Haitao Zhang;Dacheng Zhang;Xianzhong Sun;Yanwei Ma
中科院分区：
文献类型：
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作者：
Xiong Zhang;Pengmei Yu;Haitao Zhang;Dacheng Zhang;Xianzhong Sun;Yanwei Ma
在这项工作中，开发了一种快速水热方法来合成由超薄水钠锰矿型MnO2纳米片组装的分级多孔纳米结构，而不使用任何模板和表面活性剂。通过X射线衍射、扫描电子显微镜、透射电子显微镜、X射线光电子能谱、N2吸附-脱附等温线和热重分析等手段对产物的微观结构、形貌和热稳定性进行了表征。通过循环伏安法、恒电流充放电和电化学阻抗谱测量，在 1M Na2SO4 电解质中研究了所制备的 MnO2 作为超级电容器电极材料的电化学性能，在 0.3Ag−1 的电流密度下实现了 269Fg−1 的比电容。 1Ag−1 循环 2000 次后，比电容保持率和库仑效率分别为 94% 和 98%。此外，还以MnO2为正极、活性炭为负极，在1M Na2SO4电解液中制备了非对称超级电容器，电池电压为2V。
In this work, a rapid hydrothermal method has been developed to synthesize hierarchical porous nanostructures assembled from ultrathin birnessite-type MnO2nanosheets without using any template and surfactant. The microstructure, morphology, and thermal stability of the products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, N2adsorption–desorption isotherms, and thermal gravimetric analysis. The electrochemical properties of the as-prepared MnO2as an electrode material for supercapacitor were investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy measurements in 1M Na2SO4electrolyte, and a specific capacitance of 269Fg−1was achieved at a current density of 0.3Ag−1. The specific capacitance retention and coulombic efficiency were 94% and 98% respectively after 2000 cycles at 1Ag−1. Furthermore, asymmetric supercapacitor was also fabricated with MnO2as the positive electrode and activated carbon as the negative electrode in 1M Na2SO4electrolyte with the cell voltage to 2V.