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Local reversed currents and degradation phenomena in long-term tested PEFC

Reissner, R. and Schulze, M. and Haug, A. and Escribano, S. and Guétaz, L. and Friedrich, K. Andreas (2011) Local reversed currents and degradation phenomena in long-term tested PEFC. 2nd International Workshop On Degradation Issues On Fuel Cells, 21.-23. September 2011, Thessaloniki, Griechenland.

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Abstract

In order to improve the long term stability of PEFC MEAs the investigation and understanding of degradation mechanisms depending on the operating conditions is of major importance. Long term tests up to 850 hours were performed in a single channel serpentine cell at constant load and in humid conditions at 80°C. The cell was equipped with a device to measure the current density distribution across the cell area with a local resolution of 0.5 cm . At regular intervals the constant operation was interrupted for a polarisation curve. The MEA was prepared at CEA using a E87-05S AQUIVION membrane with sub-gaskets, Pt/C catalyst by TKK and the GDL 25BC by SGL., In parallel flow as well as counter-flow of the gases after approximately 500 hours of operation locally reversed currents were observed at low load. The position with negative current flow was always close to the cathode inlet of the cell. At nominal load no major degradation of the current density was observed at this position in the cell. SEM, EDX, TEM, IR spectroscopy and IR microscopy measurements were performed on the MEAs after approximately 800 hours of operation investigating the GDL back side as well as cross sections and details. IR microscopy revealed very inhomogeneous PTFE distribution at the anode backing after operation. Some depositions of Si were observed that were washed out from the cell sealing but should not have major influence on the local behaviour. Different levels of Pt particle degradation were observed in the different zones of the cell. Structural damage of the membrane could be a reason of degradation

Item URL in elib:https://elib.dlr.de/71187/
Document Type:Conference or Workshop Item (Poster)
Title:Local reversed currents and degradation phenomena in long-term tested PEFC
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Reissner, R.regine.reissner (at) dlr.deUNSPECIFIED
Schulze, M.mathias.schulze (at) dlr.deUNSPECIFIED
Haug, A.andrea.haug (at) dlr.deUNSPECIFIED
Escribano, S.CEA, DRT-LITEN-DEHT-LCPEMUNSPECIFIED
Guétaz, L.CEA, DRT-LITEN-DEHT-LCPEMUNSPECIFIED
Friedrich, K. AndreasAndreas.Friedrich (at) dlr.deUNSPECIFIED
Date:21 September 2011
Refereed publication:No
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Keywords:Brennstoffzelle; MEA-Tests; Degradation
Event Title: 2nd International Workshop On Degradation Issues On Fuel Cells
Event Location:Thessaloniki, Griechenland
Event Type:international Conference, Workshop
Event Dates:21.-23. September 2011
Organizer:Joint Research Centre - Institute for Energy
HGF - Research field:Energy
HGF - Program:Efficient Energy Conversion (old)
HGF - Program Themes:E EV - Energy process technology (old)
DLR - Research area:Energy
DLR - Program:E EV - Energy process technology
DLR - Research theme (Project):E - Elektrochemische Prozesse (old)
Location: Stuttgart
Institutes and Institutions:Institute of Engineering Thermodynamics > Electrochemical Energy Technology
Deposited By: Reißner, Regine
Deposited On:26 Oct 2011 11:04
Last Modified:01 Dec 2018 19:47

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