Microwave synthesis of graphene/magnetite composite electrode material for symmetric supercapacitor with superior rate performance

Pristine Fe3O4 and Fe3O4-graphene composites were synthesized by using a green and low cost urea-assisted microwave irradiation method and were utilized as electrode materials for symmetric supercapacitor applications. The Fe3O4-graphene symmetric cell exhibited a better electrochemical performance than that of the Fe3O4 cell with enhanced rate performances. The Fe3O4-graphene symmetric cell delivered a stable discharge capacitance, energy and power densities of about 72 F g(-1), 9 Wh kg(-1) and 3000 W kg(-1), respectively at 3.75 A g(-1) current density over 100 000 cycles between 0-1 V. The impedance studies also suggested that the Fe3O4-graphene symmetric cell showed lower resistance and high conductivity due to the small particle size, large surface area and good interaction between Fe3O4 particles and graphene layers.