Flexible electrodes of MnO 2 /CNTs composite for enhanced performance on supercapacitors

Abstract The synthesis and capacitance performance of flexible Manganese dioxide (MnO 2 )/carbon nanotube (CNTs) composite films were systematically studied in this paper. Firstly, MnO 2 nanosheets were successfully deposited onto the CNTs paper via a self-controlled redox process in KMnO 4 solution. The nanostructured MnO 2 /CNTs composite films with hierarchical porous structure could be directly fabricated as supercapacitor electrodes without binder or conductive agents. The crystalline and morphology properties of composites were studied by X-ray diffraction, Raman scattering, Scanning electron microscope and Transmission electron microscope. By electrochemical measurement of the as-fabricated flexible supercapacitor electrode, it achieved the area specific capacitance of 1980 F/m 2 with the good capacitance retention of 87% over 3000 cycles at a current density of 10 A/m 2 . The enhanced electrochemical properties could be ascribed to the porous architecture for fast ion diffusion, the conductive CNTs paper and the controlled morphology. Moreover, the symmetric supercapacitor delivered an energy density of 177 Wh/m 2 at a power density of 250 W/m 2 and maintained an energy density of 138 Wh/m 2 at a power density of 5 kW/m 2 . The research in this paper suggested that this ultralight and flexible electrode could be the promising candidates for wearable energy storage devices.