Enhanced Energy Density of Supercapacitors Using Hybrid Electrodes Based on Fe2O3 and MnO2 Nanoparticles

A major limitation of transition metal oxide-based electrodes for supercapacitors is their low energy densities. Since the energy density is proportional to the specific capacitance and square of the operating voltage, extending the voltage window of the electrode as well as enhancing contacts with electrolyte is of utmost importance. In this paper, we focus on the hybrid electrode based on Fe 2 O 3 and MnO 2 nanoparticles (NPs) which have different redox potential ranges, aiming for the increase of the specific capacitance and operating voltage window simultaneously. The hybrid Fe 2 O 3 /MnO 2 NPs-based electrode exhibited significantly improved energy density of 12.5 Wh/kg at a power density of 4500 W/g. The energy density of the hybrid electrode is 3.8 times and 1.3 times larger than that of the Fe 2 O 3 and MnO 2 single electrode, respectively.