Nanostructured Ternary Electrodes for Energy-Storage Applications

A three-component, flexible electrode is developed for supercapacitors over graphitized carbon fabric, utilizing ?-MnO2 nanoflowers anchored onto carbon nanotubes (?-MnO2/CNT) as spacers for graphene nanosheets (GNs). The three-component, composite electrode doubles the specific capacitance with respect to GN-only electrodes, giving the highest-reported specific capacitance (308 F g-1) for symmetric supercapacitors containing MnO2 and GNs using a two-electrode configuration, at a scan rate of 20 mV s-1. A maximum energy density of 43 W h kg-1 is obtained for our symmetric supercapacitors at a constant discharge-current density of 2.5 A g-1 using GN(?-MnO2/CNT)-nanocomposite electrodes. The fabricated supercapacitor device exhibits an excellent cycle life by retaining similar to 90% of the initial specific capacitance after 5000 cycles.