Degradation effects in polymer electrolyte membrane fuel cell stacks by sub-zero operation—An in situ and ex situ analysis

Alink, Robert; Gerteisen, Dietmar; Oszcipok, M.

doi:10.1016/j.jpowsour.2008.03.074

Cited by 105 publications

(48 citation statements)

References 23 publications

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“…Similar results were obtained by Koiwai et al [295] as conductivity reduced from 100 to ~1 mS.cm -1 with temperature dropping from 40˚C to -40˚C. According to Alink et al [277], the decrease in membrane conductivity under sub-zero temperatures is attributed to membrane dehydration as a result of changes in the capillary pressure at the membrane/catalyst interface. They explained that during the heating process, the phase transition from ice to liquid water results in an increase of the capillary pressure leading to expansion of the membrane channels and increase of conductivity.…”

Section: Ice Formationsupporting

confidence: 78%

“…The environmental scanning electron microscopy (ESEM) observations made by Alink et al [277] revealed a significant increase in the porosity of a damaged MEA when wet stack underwent freeze/thaw cycling. This led to the exposure of the catalyst layer and further decrease in its surface area by Pt particles detachment.…”

Section: Ice Formationmentioning

confidence: 99%

“…This includes scenarios like fuel crossover [273,274], catalytic combustion as a result of pinhole formation [272,273], fuel/oxidant starvation caused by water flooding in cracked regions [132,275], accelerated catalyst erosion due to further exposure of the electrochemical surface area [276,277], and increase in the ohmic resistance of the cell reflecting the increase in bulk resistivity (interfacial contact resistance) of the damaged layers [76,278,279]. Visual evidence of pinhole formation and micro-cracking on the surface of the membrane is provided in Figure 12a .…”

Section: Ice Formationmentioning

confidence: 99%

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Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

Ous

Arcoumanis

2013

Journal of Power Sources

132

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This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractThis review paper summarises the key aspects of Proton Exchange Membrane Fuel Cell (PEMFC) degradation that are associated with water formation, retention, accumulation, and transport mechanisms within the cell. Issues related to loss of active surface area of the catalyst, ionomer dissolution, membrane swelling, ice formation, corrosion, and contamination are also addressed and discussed. The impact of each of these water mechanisms on cell performance and durability was found to be different and to vary according to the design of the cell and its operating conditions. For example, the presence of liquid water within Membrane Electrode Assembly (MEA), as a result of water accumulation, can be detrimental if the operating temperature of the cell drops to sub-freezing.The volume expansion of liquid water due to ice formation can damage the morphology of different parts of the cell and may shorten its life-time. This can be more serious, for example, during the water transport mechanism where migration of Pt particles from the catalyst may take place after detachment from the carbon support. Furthermore, the effect of transport mechanism could be augmented if humid reactant gases containing impurities poison the membrane, leading to the same outcome as water retention or accumulation.Overall, the impact of water mechanisms can be classified as aging or catastrophic. Aging has a longterm impact over the duration of the PEMFC life-time whereas in the catastrophic mechanism the impact is immediate. The conversion of cell residual water into ice at sub-freezing temperatures by the water retention/ accumulation mechanism and the access of poisoning contaminants through the water transport mechanism are considered to fall into the catastrophic category. The effect of water mechanisms on PEMFC degradation can be reduced or even eliminated by (a) using advanced materials for improving the electrical, chemical and mechanical stability of the cell components against deterioration, and (b) implementing effective strategies for water management in the cell.

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Section: Ice Formationsupporting

confidence: 78%

Section: Ice Formationmentioning

confidence: 99%

Section: Ice Formationmentioning

confidence: 99%

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Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

Ous

Arcoumanis

2013

Journal of Power Sources

132

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“…In our previous work, we examined the damage caused by water freezing in the porous structures of GDL and electrode by in situ stack experiments, as well as by ex-situ ESEM investigation [19]. In the ESEM, water was condensed, frozen and sublimated for 10 times.…”

Section: Original Research Papermentioning

confidence: 99%

Investigating the Water Transport in Porous Media for PEMFCs by Liquid Water Visualization in ESEM

2011

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A novel ex situ method of investigating the water transport in porous media for PEM fuel cells with an environmental scanning electron microscope (ESEM) is introduced. By applying two different experimental methods, a liquid water pressure gradient is created which is necessary for the liquid water transport in porous media. The first method relies on water condensation on the bottom surface of the GDL to introduce a liquid phase into the porous media. The second method applies an external pressure gradient. The relevance of the methods is shown by visualizing the water formation and transport in different GDL materials with the high spatial resolution of an ESEM. In all experiments, the fingering effect, proposed by other researchers could be confirmed. However, the water formation on the surface of the GDLs is not consistent with the common idea of water formation in GDLs. The methods were also used to investigate the advantageous effect of laser perforating GDLs on fuel cell performance. The water transport visualization near a hole of a laser perforated GDL supports the assumptions of lower liquid water saturation in the GDL (due to effective water transport in the channels), and larger in-plane water transport towards the perforations

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“…One of the reasons could be that it would be easier to study and define operating conditions for aeronautic applications after broadening the understanding of environmental effects on PEMFC performance and lifetime. Research on operating conditions is predominantly limited to stationary and terrestrial conditions [31][32][33][34][35][36][37][38][39]. Information obtained on effect of aeronautic conditions on PEMFC will assist in defining the optimum operating conditions.…”

Section: ] 2015mentioning

confidence: 99%

PEMFC for aeronautic applications: A review on the durability aspects

et al. 2017

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Proton exchange membrane fuel cells (PEMFC) not only offer more efficient electrical energy conversion, relative to on-ground/backup turbines but generate by-products useful in aircraft such as heat for ice prevention, deoxygenated air for fire retardation and drinkable water for use on-board. Consequently, several projects (e.g. DLR-H2 Antares and RAPID2000) have successfully tested PEMFC-powered auxiliary unit (APU) for manned/unmanned aircraft. Despite the progress from flying PEMFC-powered small aircraft with 20 kW power output as high as 1 000 m at 100 km/h to 33 kW at 2 558 m, 176 km/h [1-3], durability and reliability remain key challenges. This review reports on the inadequate understanding of behaviour of PEMFC under aeronautic conditions and the lack of predictive methods conducive for aircraft that provide real-time information on the State of Health of PEMFCs. Highlights: The main research findings are -To minimize performance loss due to high altitude and inclination by adjusting cathode stoichiometric ratio. -To improve quality of oxygen-depleted air by controlling operating temperature and stoichiometric ratio. -Need to devise real time prediction methods conducive for determining PEMFC SoH in aircraft.

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Degradation effects in polymer electrolyte membrane fuel cell stacks by sub-zero operation—An in situ and ex situ analysis

Cited by 105 publications

References 23 publications

Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

Degradation aspects of water formation and transport in Proton Exchange Membrane Fuel Cell: A review

Investigating the Water Transport in Porous Media for PEMFCs by Liquid Water Visualization in ESEM

PEMFC for aeronautic applications: A review on the durability aspects

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