FUEL 151 |
| Researchers have shown that a delicate balance exists between degree of hydration and proton conductivity in typical H2/O2 fuel cell polymer electrolyte membranes. We have developed a hypothesis that when fully hydrated, water and proton transport in these films are linked, and that performance in both areas depends on polymer structure. As a first test, several composite carboxylate/sulfonate Nafion samples were prepared, allowing adjustment of the water permeability by changing the relative amount of carboxylate terminated side chains in a film. Next, room temperature proton conductivity and water permeability experiments were performed. Results show that water permeability and proton conductivity are linked: as carboxylate content increases, water permeability decreases exponentially and proton conductivity decreases linearly. We comment on relative contributions from different conduction mechanisms and propose that new PEM materials might be quickly and efficiently compared to currently-available technologies by simple conductivity and water permeability tests.
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Fuel Cell Chemistry and Operation
9:00 AM-12:05 PM, Tuesday, 12 September 2006 Palace -- Gold Ballroom, Oral
Division of Fuel Chemistry |