Electrophoretic deposition of MnO2-coated carbon nanotubes on a graphite sheet as a flexible electrode for supercapacitors

A flexible electrode was prepared by microwave heating deposition of manganese oxide (MnO2) on carbon nanotubes (CNTs) followed by electrophoretic deposition of the MnO2-coated CNTs on a flexible graphite sheet (FGS). The prepared MnO2-coated CNTs were characterized by scanning and transmission electron microscopy, and X-ray diffraction. A uniformly thin nano-scale MnO2 coating was formed on the surface of the CNTs. The MnO2-coated CNTs-FGS electrode showed highly capacitive behaviour in the 0.5 M Na2SO4 aqueous solution, with a specific capacitance of 442.9 F/g based on MnO2 at 2 mV/s. It exhibited an excellent cycling stability with no more than 1.1% capacitance loss after 1000 cycles at 50 mV/s.