Composite supercapacitor electrodes by electrodeposition of MnO 2 on MWCNT felt directly grown on aluminum

Abstract

Manganese oxide \ carbon nanotube (CNT) thin film electrodes were fabricated by direct growth of a carbon nanotube layer on aluminum substrate (i.e. a commercially viable material for use as current collector) by chemical vapor deposition, in the presence of an electrochemically deposited thin film nickel catalyst, followed by anodic electrodeposition of MnO 2 . A proof of concept of this approach is demonstrated showing that the fabrication process, even in its simplest and unsophisticated implementation-notably without any deliberate effort to control the CNT growth arrangement and consequently the composite microstructure-allows the preparation of MnO 2 /CNT/Al prototype electrodes having almost a three-fold increase in capacitance compared to MnO 2 /Ni electrodes and, more significantly, comparing favorably with composite electrodes of similar design and fabrication. MnO 2 /CNT/Al electrodes ensured also improved cyclic stability compared to the reference case of MnO 2 /Ni electrodes. The proposed scheme is an effective procedure for the fabrication of thin film composite MnO 2 /CNT/Al electrodes, which may be amenable to significant improvements by tailoring thickness and microstructure of the CNT scaffold and manganese oxide film. Furthermore, a similar process scheme, may be proposed for the fabrication of active electrodes of different scopes with a proper choice of the substrate.