The location of Nation R in solid-polymer-electrolyte-fuel-cell electrodes was investigated by porosimetry and scanning microprobe analysis. At low Nation loadings, the polymeric electrolyte uniformly fills the micro-and macropores of the electrode structure and increases its ionic conductivity. The pores are completely filled in the range from 0.8 to 1.0 mg of Nafion]cm 2 of electrode, and further addition of polymer results in the formation of a film on the external surface of the electrode. This film causes an additional resistance in series with the ionic resistance in the active layer. Impedance spectroscopic measurements of electrodes with different Nation loadings provided evidence for a variation of ionic resistance with the amount of polymer. The comparison of impedance data with polarization tests indicates that, at least for our formulations, the ionic resistance is the main factor which controls the electrochemical performance. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 155.97.178.73 Downloaded on 2014-11-26 to IP
ABSTRACTWe describe a study of the oxygen reduction kinetics at the Pt/recast Nation | interface employing a minicell based on a filmed microelectrode. The experimental conditions are identical to those in polymer-electrolyte fuel cells in that the recast ionomer electrolyte is exposed only to water vapor. We find that the interfacial rate of oxygen reduction near 0.9 V is similar for the Pt/recast ionomer interface and for Pt immersed in dilute aqueous acid solutions. A significant loss of oxygen reduction activity occurs when the recast ionomer electrolyte loses water. We discuss a possible evaluation of catalyst utilization in polymer electrolyte fuel cells.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 155.97.178.73 Downloaded on 2014-11-26 to IP
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.