Development of new nanocomposite based on nanosized-manganese oxide and carbon nanotubes for high performance electrochemical capacitors

We report the synthesis of a new composite electrode based on nanosized-manganese oxide and carbon nanotubes (CNTs) by electrophoretic deposition of CNTs on a stainless steel (SS) substrate followed by direct spontaneous reduction of MnO4− ions to MnO2 to form the multi-scaled SS–CNT–MnO2 electrode. The resulting material was characterized by scanning electron microscopy, energy dispersive X-ray analysis, cyclic voltammetry and galvanostatic charge–discharge in a 0.65 M K2SO4 aqueous solution. The binderless SS–CNT–MnO2 nanocomposite electrode shows a very high specific capacitance of 869 F/g of CNT–MnO2 and good stability during long galvanostatic charge–discharge cycling. To the best of our knowledge, this is one of the highest capacitance for manganese oxide electrode ever reported. In addition to its applicability in electrochemical capacitors, this methodology could be extended to develop other high performance nanocomposite material electrodes based on carbon nanotubes and metal oxide for the future generation of electrochemical power sources.