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O: Fachverband Oberflächenphysik
O 47: Methods: Scanning probe techniques II
O 47.4: Talk
Thursday, March 26, 2009, 11:15–11:30, SCH A316
Structural investigations of membrane electrode assemblies (MEA) in fuel cells via environmental scanning electron microscopy (ESEM) — •Susanne Zils1, Nathalie Benker2, and Christina Roth1 — 1Institute for Materials Science, TU Darmstadt, Petersenstr. 23, 64287 Darmstadt, Germany — 2Institute of Applied Geosciences, TU Darmstadt, Schnittspahnstraße 9, 64287 Darmstadt, Germany
Detailed studies to investigate the contact between the ion- and electron-conducting parts of a MEA of a polymer electrolyte membrane fuel cell (PEMFC) have only been performed by SEM and TEM up to now. These methods exclude the investigation of MEAs under realistic conditions. To obtain significant information of the structure under quasi in-situ conditions ESEM is used in this work. This technique allows for studying the MEAs under different temperatures as well as under different relative humidities.
The ESEM measurements were carried out with a Quanta 200F (FEI company, Netherlands) equipped with a field emission gun and an energy dispersive X-ray detector for elemental analysis.
During the experiments, relative humidities between 5% and 100% at defined temperatures have been adjusted. Images and movies have been recorded to investigate structural changes in the electrodes as well as on the interface between the polymer electrolyte membrane and the electrodes. Further experiments shall allow us to investigate the influence of ice formation on the electrode structure and the membrane electrode interface.