Nickel oxide/expanded graphite nanocomposite electrodes for supercapacitor application

Nickel oxide/expanded graphite (NiO/EG) nanocomposites with different loading of EG were prepared through chemically depositing Ni(OH)(2) in EG followed by thermal annealing and characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET) isotherm and electrochemical measurements. The prepared NiO/EG composites were found to be crystalline and highly porous with high specific surface area and pore volume. SEM analysis reveals uniform porous morphology for NiO in the NiO/EG-60 nanocomposites which shows good specific capacitance (510 F g(-1)) at a current density of 100 mA g(-1) in 6 mol L-1 KOH measured by chronopotentiometry employing a three-electrode system. The specific capacitance retention of the NiO/EG-60 nanocomposites was found to be ca. 95% after 500 continuous galvanostatic charge-discharge cycles, indicating that the NiO/EG nanocomposites can become promising electro-active materials for supercapacitor application.