Starting from a 5 wt% ion power Nafion® solution and dissolving the dry residue in a suitable solvent (10 wt% solution in dimethylacetammide),re-cast Nafion films were developed for polymer electrolyte fuel cells (PEFCs) application. The used Doctor-Blade casting technique allowed toprepare scaled-up membranes comparable to the commercial Nafion ones with good mechanical resistance, thickness homogeneity and an excellentreproducibility.The differences between the re-cast membrane nanostructure and that of the commercial Nafion were investigated by synchrotron small-angleX-ray scattering. The obtained re-cast membrane shows at ambient conditions a semi-crystalline structure with a typical correlation length ofabout 86 °A and an intercluster Bragg distance of 37 A° , quite different from the values of commercial film. Observation on the swelling of the filmsrevealed that the semi-crystalline structure, once soaked in water, swells less than the ionomeric part, leading to an unusual small-angle X-rayscattering (SAXS) profile in which the matrix and the ionomer peak are significantly overlapped.The ionic conductivity measured at T=80 ◦C shows slightly higher values for the re-cast Nafion membrane. A power density of about0.490Wcm−2 at 0.6V and at T=80 ◦C in humidified hydrogen/air was obtained for the developed membrane.
|Numero di pagine||9|
|Rivista||Journal of Membrane Science|
|Stato di pubblicazione||Published - 2006|
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