Nanostructured Multilayer Manganese Dioxide/Nickel/Copper Sulfite (MnO2/Ni/CuS) Composite Films for Electrochemical Applications

Nanostructured multilayer manganese dioxide/nickel/copper sulfite (MnO₂/Ni/CuS) composite films were successfully deposited on supporting polyethylene terephathalate (PET) substrate through the sequential deposition of CuS, Ni and MnO₂ thin films by chemical bath deposition, electrodeposition, and horizontal submersion deposition techniques, respectively. Deposition of each thin-film layer was optimized through varying deposition parameters and conditions associated with specific deposition technique. Both CuS and Ni thin films were optimized for their electrical conductivity whereas MnO₂ thin film was optimized for its microstructure and charge capacity. The electrochemical properties of nanostructured multilayer MnO₂/Ni/CuS composite films were evaluated by cyclic voltammetry as electrode materials of electrochemical capacitor prototype in a dual planar device configuration. Cyclic voltammograms in mild Na₂SO₄ aqueous electrolyte exhibited a featureless and almost rectangular shape which was indicative of ideal capacitive behavior and high cycling reversibility for prolonged cycling up to 1,500 cycles. Nanostructured multilayer MnO₂/Ni/CuS composite films on supporting polyethylene terephathalate (PET) substrate could potentially be utilized as electrode materials for the fabrication of high performance electrochemical capacitors.