Carbon nanotube arrays supported manganese oxide and its application in electrochemical capacitors

Manganese oxide (MnOx) has been coated on carbon nanotubes (CNTs) and fabricated as the electrodes for electrochemical capacitors (ECs) by cathodic electrodeposition. In the process, randomly oriented CNT arrays are grown directly onto the Ti/Si substrates by chemical vapor deposition method. Potentiostatic method has been utilized for cathodic electrodeposition of MnOx onto the surface of CNTs while immersed in KMnO4 solution. The highly porosity and fibrous microstructure of the as-prepared MnOx/CNT electrode is beneficial for the electrolyte access to the active material, whereas CNTs provide improved electronic conductivity. Electrochemical investigations show that the increase in the loading mass of MnOx results in a significant reduction in the specific capacitances (SCs) of the MnOx/CNT electrodes. The MnOx/CNT electrode with MnOx loading mass of 50 mu g shows a high SC of 400 F g(-1) with good long cycle stability at a current density of 10 A g(-1), suggesting its potential application in ECs.