<p> Today' s commercial proton exchange membranes for fuel cell applications use a
liquid electrolyte such as water to facilitate the conduction process. The vapour pressure
of water limits the operating temperature of a fuel cell, resulting in a decrease in
efficiency as the electrolyte evaporates. Anhydrous electrolytes such as acidified
polybenzimidazole or poly(vinyl-4-imidazole) are able to transport ions without using
water as an electrolyte. </p> <p> The mechanism of ion transport involves the structural diffusion of the ions
through the solid-state lattice. Compounds modeling the basic modes of the ionic
conductivity are used in the solid-state nuclear magnetic resonance (NMR) investigation.
The hydrogen-bonding structures of model compounds are established using diffraction
paired with 1H solid-state double quantum NMR. The structural studies of the
compounds reveal a continuous network of hydrogen bonded molecules. The structural
motif is based on strong N-H••O and 0-H••O hydrogen bonds between the ions of the
material. The dynamics of the hydrogen bonds observed in the 1H NMR and the
multinuclear studies using the CODEX (Centerband Only Detection of EXchange) pulse
sequence define the mechanism of ionic conductivity in these model compounds. </p> <p> These solid-state NMR techniques are then applied to a novel electrolyte material
consisting of a solid electrolyte inside the pores of a host polymer material. This new
material is able to transport protons at high temperatures without the use of an aqueous
electrolyte. The properties and mechanism of ion transport is investigated using solid
state NMR and impedance spectroscopy. </p> / Thesis / Doctor of Philosophy (PhD)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/19377 |
| Date | 02 1900 |
| Creators | Traer, Jason |
| Contributors | Goward, G. R., Chemistry |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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