Research On The Performance Of Modified Graphene As The Electrode Materials Of Supercapacitor

Supercapacitors, electrochemical capacitors or electrochemicaldouble layer capacitors have been extensively investigated and are beingdeveloped with the advantage of high specific power as new energystorage devices. Supercapacitors, as charge-storage devices exhibitinghigh-power density, excellent reversibility and cycleability, haveattracted tremendous attention. Most research in this area has beenfocused on the development of different electrode materials such asvarious forms of carbon, conducting polymers and transition metaloxides. In all carbon materials, grphene has been conceived as apromising supercapacitive material because of its large specific surfacearea, high electron mobility and other advantages.We synthesize grapheme by oxidation-reduction method. SEM, TEM,XRD, infrared spectroscopy, Raman spectroscopy and adsorption anddesorption method were used to research the surface morphology,preparation mechanism, specific surface area, pore size andelectrochemical performance of graphene. We use a quick and easymethod to synthesize graphene-MnO2composites through the self-limiting deposition of nanoscale MnO2on the surface of grapheneunder microwave irradiation for improving electrochemical properties ofgrapheme. SEM, TEM and XRD were used to study the surface area,profile of composite. The performance of electrochemical capacitorsusing the modified grapheme as electrode materials was investigated bycyclic voltammograms, alternating current impedance, and constantcurrent charge/discharge. Results showed that composite had an obviouspseudo-capacitance effect. This effect was coupled with the electricaldouble layer capacitance of graphene to form a complex capacitance sothat the specific capacitance of modified grapheme could be as high as237F/g. In addition, the tested capacitor with modified graphemeelectrodes showed excellent performance during reversiblecharge-discharge and also displayed high stability.