| Fuel cells are devices that directly convert the chemical energy of reactants (fuelsand oxidants) into low voltage d.c. electricity via electrochemical reactions. Theyare received widely attention due to their high efficiencies, high specific energydensities and ability to provide the necessary power. Proton exchange membranefuel cells as one type of fuel cells (PEMFC) have received widely investigated as apromising new power sources for vehicles and portable devices, due to their lowemissions and high conversion efficiency [1-3]. Proton exchange membrane, asproton conductive material is a key component of the PEMFC for transferringprotons from the anode to cathode as well as providing a barrier to the fuel gascross-leaks between the electrodes. The membranes traditionally used in PEMFCare perfluorosulfonic polymers such as Dupont Nafion?. Although they showsuperior performance in fuel cells operating at moderate temperatures (<90oC) andhigh relative humidity with pure hydrogen as fuel, the high cost, low conductivityat low humidity or high temperature and high methanol permeability of Nafion?have limited their usages [4]. Hence alternative proton exchange membranematerials are being sought [5]. Usually there are two ways to solve the problem:(1): To decrease the content of perfluoroionomers to decrease their cost bypreparing composite membranes.(2): To explore high performance proton exchange membranes materials, such assulfoanted polyacromatic polymers.In this thesis, we have introduce the sulfoanted groups into poly(aryl etherketone (PAEK) to prepare high performance proton exchange membranes. Furtherwe have characterized the structures and the properties of the resulted membranesin detail. The study showed that: sulfonated poly(aryl ether ketone) (SPAEK)polymers show very good prospective usages in PEMFC.In chapter 2, we have successfully prepared SPAEK polymers with differentsulfonated degrees by directly polymerization of sulfonated monomers. SPAEKmainly include SPEEK and SPEEKK. Further we have characterized the structuresin detail. The results showed that: the direct-sulfonation method is a powerfulmethod to prepare SPAEK polymers moreover this method can avoid thecross-linking and other side reactions.In chapter 3, the morphological changes of SPAEK membranes with differentsulfonated degrees (Ds) were investigated by small angle X-ray scattering (SAXS),atom force microscopy (AFM) and transmission electron microscope (TEM). Thesmall angle scattering maximum shifts to little vectors with sulfonated degrees (Ds)increasing. Porod analysis for SPAEK and Guinier analysis for silver exchangedSPAEK were carried out to study the microstructures of SPAEK membranes. Allthe results showed that: more clearly phase-separated structures will be formedwith the increasing of Ds of SPAEK membranes. The membranes with high Dswill provide much larger and more continuous transport channels for protons.Moreover SPEEK show more obviously phase-separated structures than SPEEKKwith the same Ds. This may be induced the different distance between thesulfoanted groups in SPAEKs.In chapter 4, we have studied the properties of the resulted SPAEKmembranes in detail. The properties mainly include mechanical properties, wateruptake, ion exchange capacity, methanol permeability, proton conductivity and fuelcell performance etc. The results showed that: SPAEK polymers show very goodpotential usages in PEMFC. Especially for SPEEK with Ds of 1.2, shows thesimilar fuel cell performance with Nafion and much lower methanol permeabilitythan Nafion. SPAEK membranes, which may be good alternative to reduceproblems associated with high methanol crossover in direct methanol fuel cells.In chapter 5, to overcome the shortcomings of the SPAEK membranes wehave prepared SPAEK composite membranes. To improve the proton conductivityof the SPAEK membranes with low sulfoanted degrees, we introduced thephosphotungstic acid into the membranes. By using the excellent protonconductive ability to increase proton conductivity of the membranes with low Ds.To improve the mechanical stability and methanol resistance of the SPAEKmembranes with high sulfonated degrees, we have introduced the amine-endedpolymers into SPAEK membranes. By using the interaction between the sulfonatedgroups in SPEEK and amine groups to improve their thermal stability andthe results showed that: more clearly phase-separated structures will be formedwith the increasing of Ds of SPAEK membranes. The membranes with high Dswill provide much larger and more continuous transport channels for protons.Moreover SPEEK show more obviously phase-separated structures than SPEEKKwith the same Ds. This may be induced the different distance between thesulfoanted groups in SPAEKs.In chapter 4, we have studied the properties of the resulted SPAEKmembranes in detail. The properties mainly include mechanical properties, wateruptake, ion exchange capacity, methanol permeability, proton conductivity and fuelcell performance etc. The results showed that: SPAEK polymers show very goodpotential usages in PEMFC. Especially for SPEEK with Ds of 1.2, shows thesimilar fuel cell performance with Nafion and much lower methanol permeabilitythan Nafion. SPAEK membranes, which may be good alternative to reduceproblems associated with high methanol crossover in direct methanol fuel cells.In chapter 5, to overcome the shortcomings of the SPAEK membranes wehave prepared SPAEK composite membranes. To improve the proton conductivityof the SPAEK membranes with low sulfoanted degrees, we introduced thephosphotungstic acid into the membranes. By using the excellent protonconductive ability to increase proton conductivity of the membranes with low Ds.To improve the mechanical stability and methanol resistance of the SPAEKmembranes with high sulfonated degrees, we have introduced the amine-endedpolymers into SPAEK membranes. By using the interaction between the sulfonatedgroups in SPEEK and amine groups to improve their thermal stability and...
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