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The Scientific World Journal
Volume 2013, Article ID 832581, 8 pages
http://dx.doi.org/10.1155/2013/832581
Research Article

Water Plasma Functionalized CNTs/MnO2 Composites for Supercapacitors

FEMAN Group, IN2UB, Department de Física Aplicada i Òptica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Catalonia, Spain

Received 3 September 2013; Accepted 28 September 2013

Academic Editors: Y. Chai and D. Qian

Copyright © 2013 Shahzad Hussain et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A water plasma treatment applied to vertically-aligned multiwall carbon nanotubes (CNTs) synthesized by plasma enhanced chemical vapour deposition gives rise to surface functionalization and purification of the CNTs, along with an improvement of their electrochemical properties. Additional increase of their charge storage capability is achieved by anodic deposition of manganese dioxide lining the surface of plasma-treated nanotubes. The morphology (nanoflower, layer, or needle-like structure) and oxidation state of manganese oxide depend on the voltage window applied during charge-discharge measurements and are found to be key points for improved efficiency of capacitor devices. MnO2/CNTs nanocomposites exhibit an increase in their specific capacitance from 678 , for untreated CNTs, up to 750 , for water plasma-treated CNTs.