Electrodeposition of nanostructured MnO₂ electrode on three-dimensional nickel/silicon microchannel plates for miniature supercapacitors

Manganese-dioxide is electrodeposited on three-dimensional nickel/silicon microchannel plates (Si-MCPs) to produce miniature supercapacitors. The nanostructured MnO₂ thin film can be clearly observed from the channels and largely contribute to the capacitance. The compositions and morphology are characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The electrochemical properties are investigated by cyclic voltammetry (CV), galvanostatic charging-discharging, and electrochemical impedance spectroscopy (EIS) in a neutral 1 M Na ₂SO₄ solution which preserves the structure of the substrate. The capacitance is 0.961 F/cm² or 323.1 F/g and the retention ratio is 91.1% after 1000 cycles thereby demonstrating the robustness and durability.