Graphene/MnO2-based composites reduced via different chemical agents for supercapacitors
- Authors
- Kim, Myeongjin; Hwang, Yongseon; Kim, Jooheon
- Issue Date
- 1-Oct-2013
- Publisher
- ELSEVIER SCIENCE BV
- Keywords
- Supercapacitor; Graphene/MnO2; Nanoneedle; Reducing effect; Electronic conductive channel; Hydrazine hydrate
- Citation
- JOURNAL OF POWER SOURCES, v.239, pp 225 - 233
- Pages
- 9
- Journal Title
- JOURNAL OF POWER SOURCES
- Volume
- 239
- Start Page
- 225
- End Page
- 233
- URI
- https://scholarworks.bwise.kr/cau/handle/2019.sw.cau/14225
- DOI
- 10.1016/j.jpowsour.2013.03.146
- ISSN
- 0378-7753
1873-2755
- Abstract
- Graphene/MnO2 composites are synthesized by the chemical reduction of GO/MnO2 using both hydrazine hydrate (H-RGO/MnO2) and sodium borohydride (S-RGO/MnO2) as reducing agents. The morphology and microstructure of the as-prepared composites are characterized by X-ray diffractometry, field-emission scanning electron microscopy, Raman microscopy, thermogravimetric analysis and X-ray photoelectron spectroscopy. Characterizations indicate that MnO2 is successfully formed on the GO surface and GO is reduced successfully by using both hydrazine hydrate and sodium borohydride as reducing agents. H-RGO/MnO2 shows higher electrical conductivity than that of S-RGO/MnO2 since it has a lower concentration of oxygen-containing functional groups. The capacitive properties of the H-RGO/MnO2 and S-RGO/MnO2 electrodes are measured using cyclic voltammetry and galvanostatic charge/discharge tests and electrochemical impedance spectroscopy in a three-electrode experimental setup using a 1 M Na2SO4 aqueous solution as the electrolyte. The H-RGO/MnO2 electrode displays a specific capacitance as high as 327.5 F g(-1) at 10 mV s(-1), which is higher than that of the S-RGO/MnO2 electrode (278.6 F g(-1)). It is anticipate that the formation of nanoneedle structures of MnO2 on graphene oxide surfaces after the hydrazine reduction procedure is a promising fabrication method for supercapacitor electrodes. (C) 2013 Elsevier B.V. All rights reserved.
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