title: The Effect of Platinum Electrocatalyst on Membrane Degradation in Polymer Electrolyte Fuel Cells.
abstract: Membrane degradation is a severe factor limiting the lifetime of polymer electrolyte fuel cells. Therefore, obtaining a deeper knowledge is fundamental in order to establish fuel cells as competitive product. A segmented single cell was operated under open circuit voltage with alternating relative humidity. The influence of the catalyst layer on membrane degradation was evaluated by measuring a membrane without electrodes and a membrane-electrode-assembly under identical conditions. After 100 h of accelerated stress testing the proton conductivity of membrane samples near the anode and cathode was investigated by means of ex situ electrochemical impedance spectroscopy. The membrane sample near the cathode inlet exhibited twofold lower membrane resistance and a resulting twofold higher proton conductivity than the membrane sample near the anode inlet. The results from the fluoride ion analysis have shown that the presence of platinum reduces the fluoride emission rate; which supports conclusions drawn from the literature.
authors.affiliation: Institute of Chemical Engineering and Environmental Technology, NAWI Graz, Graz University of Technology, Inffeldgasse 25C, Graz 8010, Austria. merit.bodner@tugraz.at.
authors.forename: Merit
authors.initials: M
authors.lastname: Bodner
authors.affiliation: Institute of Chemical Engineering and Environmental Technology, NAWI Graz, Graz University of Technology, Inffeldgasse 25C, Graz 8010, Austria. bernd.cermenek@tugraz.at.
authors.forename: Bernd
authors.initials: B
authors.lastname: Cermenek
authors.affiliation: Institute of Chemical Engineering and Environmental Technology, NAWI Graz, Graz University of Technology, Inffeldgasse 25C, Graz 8010, Austria. mija.rami@tugraz.at.
authors.forename: Mija
authors.initials: M
authors.lastname: Rami
authors.affiliation: Institute of Chemical Engineering and Environmental Technology, NAWI Graz, Graz University of Technology, Inffeldgasse 25C, Graz 8010, Austria. viktor.hacker@tugraz.at.
authors.forename: Viktor
authors.initials: V
authors.lastname: Hacker
keywords: OCV conditions; fluoride emission rate; membrane degradation; membrane resistance; polymer electrolyte fuel cell; proton conductivity; relative humidity cycling; segmented cell