Facile synthesis of well-ordered manganese oxide nanosheet arrays on carbon cloth for high-performance supercapacitors

Well-ordered manganese oxide (MnO2) nanosheet arrays (NSAs) were grown directly on carbon cloth via a simple in situ redox replacement reaction between potassium permanganate (KMnO4) and carbon cloth without any other oxidant or reductant addition. The morphology of MnO2 NSAs was examined by scanning and transmission electron microscopy and the phase structure of nanosheets (NSs) was analyzed by X-ray diffraction spectroscopy. Based on a series of time-dependent experiments, a possible growth process for this structure was proposed. The MnO2 NSAs supported on carbon cloth were directly used as integrated electrodes for electrochemical capacitors. The ordered MnO2 NSAs yielded high-capacitance performance with a high specific capacitance of 2.16 F cm(-2) at a charge and discharge current density of 5 mA cm(-2) and 1.01 F cm(-2) at 20 mA cm(-2) with a cycling ability (61.4% of the initial specific capacitance remains after 3000 cycles). The MnO2 nanosheet arrays with large surface area and high degree of ordering, combined with the flexible carbon cloth substrate can offer great promise for large-scale supercapacitor applications.