Hydrothermal synthesis of MnO2/CNT nanocomposite with a CNT core/porous MnO2 sheath hierarchy architecture for supercapacitors

• Published in: Nanoscale research letters 2012-01, Vol.7 (1), p.33-33, Article 33
• Main Authors: Xia, Hui, Wang, Yu, Lin, Jianyi, Lu, Li
• Format: Article
• Language: English
• Subjects: Chemistry and Materials Science; IFFM&AFM2011; Materials Science; Molecular Medicine; Nano Express; Nanochemistry; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering
• ISSN: 1556-276X; 1931-7573; 1556-276X
• DOI: 10.1186/1556-276X-7-33

MnO 2 /carbon nanotube [CNT] nanocomposites with a CNT core/porous MnO 2 sheath hierarchy architecture are synthesized by a simple hydrothermal treatment. X-ray diffraction and Raman spectroscopy analyses reveal that birnessite-type MnO 2 is produced through the hydrothermal synthesis. Morphological characterization reveals that three-dimensional hierarchy architecture is built with a highly porous layer consisting of interconnected MnO 2 nanoflakes uniformly coated on the CNT surface. The nanocomposite with a composition of 72 wt.% (K 0.2 MnO 2 ·0.33 H 2 O)/28 wt.% CNT has a large specific surface area of 237.8 m 2 /g. Electrochemical properties of the CNT, the pure MnO 2 , and the MnO 2 /CNT nanocomposite electrodes are investigated by cyclic voltammetry and electrochemical impedance spectroscopy measurements. The MnO 2 /CNT nanocomposite electrode exhibits much larger specific capacitance compared with both the CNT electrode and the pure MnO 2 electrode and significantly improves rate capability compared to the pure MnO 2 electrode. The superior supercapacitive performance of the MnO 2 /CNT nancomposite electrode is due to its high specific surface area and unique hierarchy architecture which facilitate fast electron and ion transport.