Facile one-step hydrothermal syntheses and supercapacitive performances of reduced graphene oxide/MnO sub(2) composites

Reduced graphene oxide (rGO)/MnO sub(2) composites were synthesized by a facile one-step hydrothermal reaction of GO and KMnO sub(4) in ammonia solution, and then used as electrode materials for supercapacitors containing electrolytes of 1 M Na sub(2)SO sub(4) aqueous solution. The structures and mo...

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Bibliographic Details
Published in:Composites science and technology 2014-01, Vol.103, p.113-118
Main Authors: Fan, Le-Qing, Liu, Gui-Jing, Zhao, Jun-Chang, Wu, Ji-Huai, Zhong, Ji, Lin, Jian-Ming, Huo, Jing-Hao, Liu, Lu
Format: Article
Language:English
Subjects:
Capacitors
Electrode materials
Graphene
Hydrothermal reactions
Mass ratios
Oxides
Scanning electron microscopy
Supercapacitors
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Summary:Reduced graphene oxide (rGO)/MnO sub(2) composites were synthesized by a facile one-step hydrothermal reaction of GO and KMnO sub(4) in ammonia solution, and then used as electrode materials for supercapacitors containing electrolytes of 1 M Na sub(2)SO sub(4) aqueous solution. The structures and morphologies of composites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectra and N sub(2) adsorption-desorption isotherms. To assess the supercapacitive performances of these materials, cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy tests of two-electrode supercapacitors were performed. GO was reduced to form rGO and 30-50 nm sized MnO sub(2) nanoparticles were in-situ grown on the rGO sheets to obtain rGO/MnO sub(2) composites simultaneously during the hydrothermal reaction. The influences of mass ratios of GO and KMnO sub(4) on the electrochemical performances of supercapacitors were investigated. In comparison with pure MnO sub(2)based supercapacitor, supercapacitors based on rGO/MnO sub(2) composites show better performances because both the specific surface areas and the electrical conductivities of electrode materials were increased by the introduction of rGO. When the mass ratio of GO and KMnO sub(4) is 2:1, rGO/MnO sub(2) composite electrode shows the highest capacitance of 205.7 F/g at a constant current density of 0.15 A/g in a two-electrode supercapacitor. Additionally, the supercapacitor exhibits high rate capability and long cyclic durability.
ISSN:0266-3538
DOI:10.1016/j.compscitech.2014.08.023