Electrochemical Performances of Nanoparticle Fe₃O₄/Activated Carbon Supercapacitor Using KOH Electrolyte Solution

In this study, activated carbon (AC)-Fe 3 O 4 nanoparticles asymmetric supercapacitor cells have been assembled and characterized in 6 M KOH aqueous electrolyte for the first time. The nanostructure Fe 3 O 4 was prepared by the microwave method. It only cost several minutes to prepare magnetite nanoparticles with average particle size of 35 nm. The electrochemical performances of the hybrid AC-Fe 3 O 4 supercapacitor were tested by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge−discharge tests. The results show that the asymmetric supercapacitor has electrochemical capacitance performance within potential range 0−1.2 V. The supercapacitor delivered a specific capacitance of 37.9 F/g at a current density of 0.5 mA/cm 2 . The result of cyclic characteristic test showed that it also can keep 82% of initial capacity over 500 cycles.