Synthesis And Supercapacitor Performance Of Graphene Oxide/Conducting Polymer Nanocomposites

Supercapacitor can combine the advantages of both battery and conventionalcapacitors. With using more times, higher power density, great capacitance andenvironment-friendly, supercapacitor has matched with battery during charging anddischarging process. It should be complementary to battery and act as secondarypower source. Currently, how to improve the electrochemical properties of thematerial to become one of the primary issues need to be resolved.This thesis have found that electrochemical performance of composites wasenhanced owning to the synergetic effect when we combine graphene oxide withconducting polymers. This thesis is distributed into four parts.The content of the first chapter is not only describe the characteristics, researchstatus, classification and energy storage mechanism of supercapacitor, but also theapplications and research progress of supercapacitor electrode materials based ongraphene, graphene oxide and conducting polymer. In the meantime, the preparationmethods of graphene oxide/conducting polymer nanocomposite are summarized. Atlast, I come up with my research view and purpose about supercapacitor electrodematerials.The second chapter exhibit preparation and electrochemical capacitanceproperties of graphene oxide/polypyrrole nanocomposite. This chapter is distributedinto two parts.1. GO/PPy intercalation composite was successfully prepared via in-situ chemicaloxidative polymerization of pyrrole monomers by using FeCl3-methyl orange (MO) asa template agent. In addition, the electrochemical properties of the composite materialswere investigated in neutral and acidic electrolytes (1mol·L-1Na2SO4and1mol·L-1H2SO4). It turned out that the GO/PPy intercalation composite displayed considerablespecific capacitances both in neutral and acid electrolyte. A higher initial capacitancewas obtained in1mol·L-1H2SO4, while the composite showed a better electrochemical cyclic stability in1mol·L-1Na2SO4.2. Polypyrrole nano-particles with an average diameter of40~50nm werefabricated using emulsion polymerization. In this process, mixed surfactant, containingcetyltrimethyl ammonium bromide (CTAB) and sodium dodecylbenzyl sulfonate(SDBS), is injected. Furthermore, GO/PPy comoposites were fabricated as the sameway and exhibited excellent electrochemical performance.The third chapter content is as follows.Polyaniline nanofibers were synthesized without any templates, surfactants, orfunctional dopants by the introduction of p-phenylenediamine as an initiator intoin-situ polymerization reaction. In addition to, using graphene oxide (GO) as thesubstrate, GO/PANI nanocomposites were synthesized by in-situ polymerization. ThePANI nanofibers exhibited the specific capacitances of497.5F·g-1at0.5A·g-1, whilethe specific capacitances of GO/PANI nanocomposites was623.0F·g-1.The fourth chapter displays preparation and electrochemical capacitanceproperties of PANI/PPy nanorods and GO/PANI/PPy ternary composites. This chapteris also distributed into two parts.1. PANI/PPy binary composites were synthesized using two steps. Firstly, thepreparative PPy powders were dissolved in deionized water. Secondly, thecation-anion mixed surfactant (CTAB-SDBS) and aniline were added. Then thePANI/PPy binary composites were obtained by in-situ polymerization reaction at lowtemperatures. The results showed that PANI successfully adhered on the surface ofPPy nanotubes and formed uniformly nanorods with higher specific capacitance.2. GO/PANI/PPy ternary composites with excellent electrochemical performancewere successfully prepared when we combined GO with PANI/PPy binary compositesto make GO sheets wrapped on the surface of PANI-PPy nanorods.