Electrochemical Properties of Hybrid Supercapacitor with Nanosized Fe3O4/activated Carbon as Electrodes

The supercapacitor using nano-structured Fe3O4 and activated carbon (AC) as electrode materials was developed. Fe3O4 magnetic nanoparticles with average particle size of 36mn were synthesized by microwave method using FeSO4.7H(2)O and ammonia as the precipitator. Three kinds of supercapacitors. Fe3O4/KOH/Fe3O4, AC/KOH/AC, Fe3O4/KOH/AC, were prepared using 6mol/L KOH as eletrolyte. Cyclic voltammetry (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy were used to study the performance of the electrodes and the supercapacitors. The results show that the operating voltage of Fe3O4/KOH/AC hybrid supercapacitor is 1.2V. When the current density is 0.2mA/cm(2) and the weight ratio of active materials (Fe3O4/AC) is 1.5, the energy density of hybrid supercapacitor is 9.25Wh/kg, which is 5.4% higher than that of AC/KOH/AC capacitor with the same electrolyte.