Approach for development of polymer electrolyte fuel cells using neutrons. Structure analysis of catalyst layers by small-angle scattering

Development of polymer electrolyte fuel cells (PEFCs) is required to realize hydrogen economy. Contrast-variation small-angle neutron scattering was measured for a catalyst layer of PEFCs to analyze the ionomer distribution on the carbon aggregates. The depth-profile of an ionomer thin film in a catalyst layer was investigated by neutron reflectometry and the water dynamics in a catalyst layer was evaluated using quasi-elastic neutron scattering. Neutron radiography was applied to distinguish frozen ice from fluid water. By using various neutron techniques, we can approach to what we could not observe in PEFCs so far. (author)