Composite Supercapacitor Electrodes by Electrodeposition of MnO2 on MWCNT Felt Directly Grown on Aluminum

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 MnO2. 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 MnO2/CNT/Al prototype electrodes having almost a three-fold increase in capacitance compared to MnO2/Ni electrodes and, more significantly, comparing favorably with composite electrodes of similar design and fabrication. MnO2/CNT/Al electrodes ensured also improved cyclic stability compared to the reference case of MnO2/Ni electrodes. The proposed scheme is an effective procedure for the fabrication of thin film composite MnO2/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.