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Reversible and Irreversible Degradation Phenomena in PEMFCs

Mitzel, Jens und Gazdzicki, Pawel und Biswas, Indro und Schulze, Mathias und Friedrich, K. Andreas (2016) Reversible and Irreversible Degradation Phenomena in PEMFCs. 21st World Hydrogen Energy Conference 2016, 2016-06-13 - 2016-06-16, Zaragoza, Spain.

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Kurzfassung

The presentation is focused on reversible and irreversible degradation phenomena in polymer electrolyte membrane fuel cells (PEMFCs). Analytical methods for the determination of component degradation will be presented and a new systematic approach for the analysis of reversible and irreversible degradation rates in an operating fuel cell will be introduced. A detailed description of voltage loss rates and particularly of the discrimination between reversible and irreversible voltage losses will be given. A major motivation of the presented work is the lack of common description procedures and determination approaches of voltage losses in durability tests of fuel cell. This issue results in severe difficulties in the comparison of results obtained by different testing facilities or within different research projects especially if only one value for a degradation rate is reported. In order to systematically analyze voltage losses we have performed single cell durability measurements of several hundreds of hours in 25 cm2 lab-scale cells. Specific test protocols containing regular refresh procedures were used for this purpose (see Figure 1). This enables distinguishing between reversible and irreversible voltage losses. To test the refresh procedures and analyze their effect on cell performance, parameters such as the duration of e.g. a soak time step have been varied. Between these refresh steps the cells were typically operated for 50 to 150 h. Conventional 5-layer MEAs with PFSA membranes, carbon supported Pt-catalysts and hydrophobized carbon fiber substrates with micro porous layers as GDLs were used for this study. For in-situ diagnostics of the operated cells polarization curves, impedance spectra, and CVs were recorded in order to determine the impact of the refresh procedures on the cells. Ex-situ methods were used to determine the causes for the reversible and irreversible voltage losses. Using different methods, detailed information about the physical composition of the individual fuel cell components can be obtained in order to optimize them and increase cell durability. Depending on the examined component and the analytical objective infrared absorption spectroscopy (FTIR), Raman, and X-ray photoemission spectroscopy (XPS) can be used to analyze the degradation effects and the sources for reversible and irreversible voltage loss during fuel cell operation. An overview of the different methods and their application will be given. It will be shown, that a combination of complementary methods is necessary to gather a comprehensive view of the occurring processes and mechanisms. As an example, depth profiling techniques combined with XPS can be used to determine the composition changes inside the fuel cell electrodes.

elib-URL des Eintrags:https://elib.dlr.de/108073/
Dokumentart:Konferenzbeitrag (Poster)
Titel:Reversible and Irreversible Degradation Phenomena in PEMFCs
Autoren:
AutorenInstitution oder E-Mail-AdresseAutoren-ORCID-iDORCID Put Code
Mitzel, JensJens.Mitzel (at) dlr.dehttps://orcid.org/0000-0001-8137-9689NICHT SPEZIFIZIERT
Gazdzicki, Pawelpawel.gazdzicki (at) dlr.dehttps://orcid.org/0000-0002-5728-7861NICHT SPEZIFIZIERT
Biswas, Indroindro.biswas (at) dlr.dehttps://orcid.org/0000-0002-6815-4204NICHT SPEZIFIZIERT
Schulze, Mathiasmathias.schulze (at) dlr.deNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Friedrich, K. Andreasandreas.friedrich (at) dlr.deNICHT SPEZIFIZIERTNICHT SPEZIFIZIERT
Datum:13 Juni 2016
Referierte Publikation:Ja
Open Access:Ja
Gold Open Access:Nein
In SCOPUS:Nein
In ISI Web of Science:Nein
Status:veröffentlicht
Stichwörter:PEMFC Degradation rates Reversible degradation Irreversible Degradation Analytical methods
Veranstaltungstitel:21st World Hydrogen Energy Conference 2016
Veranstaltungsort:Zaragoza, Spain
Veranstaltungsart:internationale Konferenz
Veranstaltungsbeginn:13 Juni 2016
Veranstaltungsende:16 Juni 2016
HGF - Forschungsbereich:Energie
HGF - Programm:Speicher und vernetzte Infrastrukturen
HGF - Programmthema:Brennstoffzellen
DLR - Schwerpunkt:Energie
DLR - Forschungsgebiet:E EV - Energieverfahrenstechnik
DLR - Teilgebiet (Projekt, Vorhaben):E - Elektrochemische Prozesse (Brennstoffzellen) (alt)
Standort: Stuttgart
Institute & Einrichtungen:Institut für Technische Thermodynamik > Elektrochemische Energietechnik
Hinterlegt von: Mitzel, Dr. Jens
Hinterlegt am:22 Nov 2016 09:22
Letzte Änderung:24 Apr 2024 20:13

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