Microwave-hydrothermal preparation of a graphene/hierarchy structure MnO2 composite for a supercapacitor--颗粒学报PARTICUOLOGY

Chen, Z., Li, J., Chen, Y., Zhang, Y., Xu, G., Yang, J., & Feng, Y. (2014). Microwave-hydrothermal preparation of a graphene/hierarchy structure MnO2 composite for a supercapacitor. Particuology, 15, 27–33. https://doi.org/10.1016/j.partic.2012.12.008

Microwave-hydrothermal preparation of a graphene/hierarchy structure MnO₂ composite for a supercapacitor

Zhong Chen ^a, Jianling Li ^a *, Yu Chen ^a, Yakun Zhang ^a, Guofeng Xu ^a, Jun Yang ^b, Ye Feng ^b

a State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, 30 College Road, Beijing 100083, China
b State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China

10.1016/j.partic.2012.12.008

Volume 15, August 2014, Pages 27-33

Received 23 October 2012, Revised 5 December 2012, Accepted 24 December 2012, Available online 7 March 2013.

E-mail: lijianling@ustb.edu.cn

Highlights

► Graphene/hierarchy structure MnO₂ composites were synthesized by microwave-hydrothermal method.

► The hierarchy structure of MnO₂ is composed of MnO₂ nanospheres and MnO₂ sheets.

► GN/MnO₂-10% electrode showed a specific capacitance of 244 F/g at 100 mA/g in 1 mol/L Li₂SO₄.

► Capacity retention of 94.3% was obtained after 500 cycles in a 1 mol/L Li₂SO₄ solution.

Abstract

Graphene/hierarchy structure manganese dioxide (GN/MnO₂) composites were synthesized using a simple microwave-hydrothermal method. The properties of the prepared composites were analyzed using field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) measurements. The electrochemical performances of the composites were analyzed using cyclic voltammetry, electrochemical impedance spectrometry (EIS), and chronopotentiometry. The results showed that GN/MnO₂ (10 wt% graphene) displayed a specific capacitance of 244 F/g at a current density of 100 mA/g. An excellent cyclic stability was obtained with a capacity retention of approximately 94.3% after 500 cycles in a 1 mol/L Li₂SO₄ solution. The improved electrochemical performance is attributed to the hierarchy structure of the manganese dioxide, which can enlarge the interface between the active materials and the electrolyte. The preparation route provides a new approach for hierarchy structure graphene composites; this work could be readily extended to the preparation of other graphene-based composites with different structures for use in energy storage devices.

Graphical abstract

Keywords

Graphene; MnO₂; Hierarchy structure; Supercapacitor

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