High-performance supercapacitors using graphene/polyaniline composites deposited on kitchen sponge

We in this study used a commercial grade kitchen sponge as the scaffold where both graphene platelets (GnPs) and polyaniline (PANi) nanorods were deposited. The high electrical conductivity of GnPs (1460 S cm⁻¹) enhances the pseudo-capacitive performance of PANi grown vertically on the GnPs basal planes; the interconnected pores of the sponge provide sufficient inner surface between the GnPs/PANi composite and the electrolyte, which thus facilitates ion diffusion during charge and discharge processes. When the composite electrode was used to build a supercapacitor with two-electrode configuration, it exhibited a specific capacitance of 965.3 F g⁻¹ at a scan rate of 10 mV s⁻¹ in 1.0 M H₂SO₄ solution. In addition, the composite Nyquist plot showed no semicircle at high frequency corresponding to a low equivalent series resistance of 0.35 Ω. At 100 mV s⁻¹, the supercapacitor demonstrated an energy density of 34.5 Wh kg⁻¹ and a power density of 12.4 kW kg⁻¹ based on the total mass of the active materials on both electrodes. To demonstrate the performance, we built an array consisting of three cells connected in series, which lit up a red light emitting diode for five minutes. This simple method holds promise for high-performance yet low-cost electrodes for supercapacitors. (paper)