Applied Research Of Graphene Composite Materials In The Supercapacitor

As a new type of energy storage device, supercapacitor has high efficiency ofcharge-discharge, specific capacitance, good cycling stability and environmentalprotection, it become a research hotspot in recent years. Graphene has larger specificsurface area, good mechanical, electricity, optics, thermodynamics property, it is oftenapplied to sensors, lithium batteries, catalysts, supercapacitor and other fields graphenehas been widely used. As organic conductive polymers, polyaniline is always uesed ingraphene/polyaniline composite material for supercapacitor electrode materials, onaccount of pseudocapacitance, capacitive of composite materials electrode improvedsignificantly. This thesis is dedicated to develop a simple and efficient preparationmethod, this graphene/polyaniline composite materials electrode has good electro-chemical performance. the main progress as follows:1. This paper use three kinds of modified Hummers method to preparation graphiteoxide, mark them as GO-1, GO-2and GO-3. Difference is that the GO-1costs the longestoxidation time, the GO-3costs the least dosage of oxidant, for the GO-2,the costs ofoxidation time and dosage of oxidant is between GO-1and GO-2. According to the resultof test, it shows that the GO-2method preparative graphite oxide layer spacing ismoderate, structure ordering is better, and with more functional such as hydroxyl, carboxyland epoxy group, synthesize considering the structure and morphology, the GO-2methodpreparative graphite oxide make for preparation graphite/polyaniline composite.2. This paper adopts different oxidant and use in situ polymerization method to synthesis polyaniline, the L-PANI method use ammonium persulfate as oxidant, theamount of substance ratio of1:1with aniline monomers, the W-PANI method use MnO2asoxidant, the mass ratio of1:1with aniline monomers. The L-PANI method synthesis ofpolyaniline has short rod structure, uniform of the poresize distribution, without severecascading phenomenon. Dispersion the GO-2graphite oxide powders into the hydrochloricacid to preparation graphene oxide dispersion liquid, using L-PANI method compoundgraphene oxide/polyaniline composite material. Useing infrared spectrum analysis, X-raydiffraction analysis, scanning electron microscopy analysis and thermogravimetric analysis,the results showed that a new chemical bond between graphene oxide C=O of hydroxyland–NH2of polyaniline.3. Using common chemical reduction method and hydrothermal reduction method,with different reductant preparation graphene/polyaniline composite material, mark themfor HrG/PANI and PANI/SrG. Useing infrared spectrum analysis, X-ray diffractionanalysis, scanning electron microscopy analysis and thermogravimetric analysis, we foundthat the two methods can both reductive functional groups of graphene oxide, under thehigh temperature and high pressure, the structure of SrG/PANI composites is broken, as aresult, it has better performance of HrG/PANI composites than that of SrG/PANIcomposite material.4. This paper use graphene that make of common chemical reduction method, theL-PANI method synthesis of polyaniline and the method of HrG/PANI reduction ofgraphene/polyaniline composite material to prepare electrodes, under the three electrodesystem test their performance of cyclic voltammograms and ac impedance. Results showthat under the scanning rate of10mV/s, the specific capacitance of graphene/polyanilinecomposites electrode reached74.64Fg-1.