[Show abstract][Hide abstract] ABSTRACT: Sulphated zirconia-added Nafion membranes were prepared and used as polymer electrolyte separators in H2-air fuel cells. The cell performances of the composite membrane were compared with those of an unmodified Nafion membrane having the same thickness. The cell response was studied by means of voltage–current dependence, in situ impedance spectroscopy and current interrupt-based cell resistance. The effect of temperature on the cells behaviour was evaluated. When using the composite membrane as an electrolyte a general enhancement was found, both in terms of power density delivered and ohmic resistance. Moreover, the high-temperature impedance response of the zirconia-doped Nafion-based cell was highly improved, showing a wellcontrolled charge transfer resistance.
[Show abstract][Hide abstract] ABSTRACT: The effect of an acidic inorganic additive, i.e. sulfated zirconia, on Nafion-based polymer electrolytes is evaluated by comparing the properties in terms of conductivity and fuel cell performance of a composite sulfated zirconia-added Nafion membrane with those of an additive-free Nafion membrane. The peculiar surface properties of the selected filler promote a higher hydration level and a higher conductivity for the composite membrane under unsaturated conditions, i.e. at 20% RH. Tests on H2-air fully humidified cells, monitored at 70 °C and at atmospheric pressure, reveal small differences when passing from a plain Nafion to a composite Nafion/sulfated zirconia membrane as electrolyte. However, remarkably great improvements are observed for the composite membrane-based cell when the comparison tests are run at low relative humidity and high temperature, this outlining the beneficial role of the sulfated zirconia additive.
No preview · Article · Aug 2008 · Journal of Power Sources