Nanostructured Ternary Electrodes for Energy‐Storage Applications

A three‐component, flexible electrode is developed for supercapacitors over graphitized carbon fabric, utilizing γ‐MnO2 nanoflowers anchored onto carbon nanotubes (γ‐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–(γ‐MnO2/CNT)‐nanocomposite electrodes. The fabricated supercapacitor device exhibits an excellent cycle life by retaining ≈90% of the initial specific capacitance after 5000 cycles.