High-performance symmetric supercapacitor device based on carbonized iron-polyaniline/nickel graphene foam

Abstract The carbonized iron-polyaniline/nickel graphene foam (C–Fe/PANI/Ni-GF) electrode was prepared by pasting a mixture of iron-polyaniline (Fe/PANI) on nickel graphene foam (Ni-GF) and carbonized under the nitrogen. For electrochemical characterization, the as-prepared electrode material was evaluated in both three and two-electrode (i.e. symmetric) cell configurations using 1 M NaNO3 electrolyte. The symmetric device exhibited a maximum energy density of 68.0 W h kg−1 and power density of 718.2 W kg−1, at a specific current of 1.0 A g−1 and the maximum potential of 1.7 V. The device further displayed long-term cycling stability with capacity retention of 91% over 10 000 galvanostatic charge-discharge cycles at 5 A g−1. The stability of the device was also tested using the voltage holding and self-discharge approach whereby a slow-discharging process was observed, which suggests the practical application of the device.