Preparation And Supecapacitor Performance Of Graphene Oxide Nanocomposites

Graphene as a new two dimensional nanomaterial is another major discocery after carbon nanotube and fullerene. Graphene has attracted lots of research interests around the world since Geim group prepared and observed with micro-mechanical stripping in2004. Supercapacitors, also known as electrochemical capacitors, have been recognized as a rapid charge/discharge energy storage devices which performance between the rechargeable batteries and the typical dielectric capacitors. Supercapacitors have shown many advantages such as:high energy density, high capacity, high power density, wide work-temperature range, excellent cycling stability, and environmentally friendly character. Graphene oxide has recently been found to exhibit exceptionally high thermal conductivity, electrical conductivity, and strength. Specifically, graphene sheets have a high tendency to restack themselves during all phases of graphene preparation and subsequent electrode production procedures, leaving behind inter graphene pore sizes that graphene oxide are not sufficient for accessibility to the electrolyte and the formation of EDLCS charges Main work as follows:1. Biomolecule-assisted Synthesis of Cobalt Sulfide/Graphene Oxide Nanocomposite for High-performance SupercapacitorCobalt sulfide/graphene oxide (CoS/GO) nanocomposite, as a novel supercapacitor material, is synthesized by a biomolecule-assisted hydrothermal process in situ reaction in the presence of graphene oxide. The as-synthesized products are characterized by XRD, SEM, TEM, BET-BJH and TG. The electrochemical property and impedance of the CoS/GO nanocomposite are studied by cyclic voltammetry and EIS ananlysis, respectively. The results show that the introduction of the GO enhanced the electrode conductivity and stability, and then improved the supercapacitive behavior of CoS/GO nanocomposite. The galvanostatic charge/discharge measurement results show that the CoS/GO nanocomposite has a high specific capacitance (550Fg-1at lAg-1) and long cycle life (over1000cycles), indicating that the CoS/GO nanocomposite is a promising material for high-performance supercapacitor. 2. Preparation and Capacitive property of polyaniline/graphene oxide nanocompositeIn this paper, the chemical polymerization method was used to prepare graphene oxide-polyaniline (CNT-PANI) nanocomposite by coating polyaniline on the surface of the graphene oxide. The product was characterized by SEM, TEM, XRD and TGA. Cyclic voltammetry and Nyquist plot were also used to investigate its electrochemical properties. The results show that the introduction of the GO enhanced the electrode conductivity and stability. Significantly, the electrochemical measurement results show that the PANI/GO composite has a high specific capacitance and long cycle life (over1000times).3. Preparation and Capacitive property of polyaniline/SnO2/graphene oxide nanocompositeThe polyaniline/SnO2/graphene oxide (PANI/SnO2/GO) composite was synthesized by a simple process. The structure and morphology of as-synthesized products were characterized by X-ray diffractometer, transmission electron microscopy, fourier transform infrared spectrograph and thermogravimetric analyzer. The electrochemical and capacitance properties were studied by by cyclic voltammetry, Nyquist plot, and charge/discharge test. The electrochemical measurement results show that the PANI/SnO2/GO composite has a high specific capacitance and long cycle life (over1000times).