Library Portal | UWC Portal | National ETDs | Global ETDs
    • Login
    Contact Us | Quick Submission Guide | About Us | FAQs | Login
    View Item 
    •   ETD Home
    • Faculty of Natural Science
    • Department of Chemistry
    • Philosophiae Doctor - PhD (Chemistry)
    • View Item
    •   ETD Home
    • Faculty of Natural Science
    • Department of Chemistry
    • Philosophiae Doctor - PhD (Chemistry)
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Synthesis of sulphonated and transition metal oxide doped polymeric nanocomposites for application in design of supercapacitors

    Thumbnail
    View/Open
    PhD (17.98Mb)
    Date
    2011
    Author
    Njomo, Njagi
    Metadata
    Show full item record
    Abstract
    To meet a fast-growing market demand for next generation portable electronic devices with higher performance and increased device functionalities, efficient electrical energy devices with substantially higher energy, power densities and faster recharge times such as supercapacitors are needed. The overall aim of this thesis was to synthesize nanostructured sulphonated polyaniline and transition metal single, binary and ternary mixed oxide doped nanocomposites with electro-conductive properties. These nanocomposites were anchored on activated graphitic carbon and used in design of asymmetric supercapacitors. Tantalum(IV)oxide, tantalum(IV)oxide-nickel(II)oxide, tantalum(II)oxide-manganese(III)oxide, tantalum(II)oxide-nickel(II)oxide-manganese(II,III)oxide nanoparticles were synthesised using modified sol-gel methods. These were then dispersed, individually, in acidic media through sonication and incorporated in-situ into the polymeric matrix during the oxidative chemical polymerization of aniline doped with poly(4-styrene sulphonic acid). These novel polymeric nanocomposites were characterised with FTIR, UV-visible, TEM, SEM, EDS, XRD to ascertain successful polymerization, doping, morphology and entrapment of the metal oxide nanoparticles. SECM approach curves and interrogation of CV revealed that these nanocomposites are conductive and electro-active. The cells showed good supercapacitor characteristics with high specific capacitances of 170.5 Fg⁻¹ in TaO₂- PANi-PSSA, 166.1 Fg⁻¹ in TaO₂-NiO-PANi-PSSA, 248.4 Fg-1 in TaO-Mn₂O₃-PANi- PSSA and 119.6 Fg⁻¹ in TaO-NiO-Mn₃O₄-PANi-PSSA. Their corresponding energy densities were calculated as 245.5 Whg⁻¹, 179.4 Whg⁻¹, 357.7 Whg⁻¹ and 172.3 Whg⁻¹ respectively. They also gave respective power densities of 0.50 Whg⁻¹, 0.61 Whg⁻¹, 0.57 Whg⁻¹ and 0.65 Whg⁻¹ and showed good coulombic efficiencies ranging between 77.97% and 83.19%. These materials are found to have a long cycle life and therefore good electrode materials for constructing supercapacitor cells.
    URI
    http://hdl.handle.net/11394/5429
    Collections
    • Philosophiae Doctor - PhD (Chemistry) [81]

    DSpace 5.5 | Ubuntu 14.04 | Copyright © University of the Western Cape
    Contact Us | Send Feedback
    Theme by 
    @mire NV
     

     

    Browse

    All of RepositoryCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    Login

    Statistics

    View Usage Statistics

    DSpace 5.5 | Ubuntu 14.04 | Copyright © University of the Western Cape
    Contact Us | Send Feedback
    Theme by 
    @mire NV