Characteristics of oxygen diffusivity and water distribution by X-ray radiography in microporous media in alternate porous layers of different wettability for moisture control in gas diffusion layer of PEFC

Utaka, Yoshio; Hirose, Ikunori; Tasaki, Yutaka

doi:10.1016/j.ijhydene.2011.04.152

Cited by 37 publications

(37 citation statements)

References 11 publications

(13 reference statements)

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“…R D = D e /D e;dry . It is seen that the predicted relative gas diffusion coefficient decreases with the water saturations S, in good agreement with the experimental data in partially saturated GDLs made of hydrophobic carbon papers by Utaka et al [5], where the threshold saturation value is about 0.6-0.7. One can easily envision that it is more difficult for gas to pass through a medium with higher water saturation.…”

Section: The Effects Of Liquid Saturationsupporting

confidence: 89%

“…For instance, gas diffusion in fibrous materials, one of the common occurrences such as mass transport through fibrous screen filters in many filtering processes, and through gas diffusion layer (GDL) in fuel cells, is considered essential in many engineering fields [3][4][5]. A deep understanding of how the fibrous microstructures affect the diffusive flux can lead to significant improvements in product design [6].…”

Section: Introductionmentioning

confidence: 99%

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Effective gas diffusion coefficient in fibrous materials by mesoscopic modeling

Guo

et al. 2017

International Journal of Heat and Mass Transfer

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Section: The Effects Of Liquid Saturationsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Effective gas diffusion coefficient in fibrous materials by mesoscopic modeling

Guo

et al. 2017

International Journal of Heat and Mass Transfer

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“…Flückiger et al, Kim et al and Utaka et al [34][35][36] presented saturation distributions in GDLs at different water inlet pressures using X-ray visualization.…”

Section: Saturation Distributionmentioning

confidence: 99%

Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

Alink

Gerteisen

2013

Energies

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In order to model the liquid water transport in the porous materials used in polymer electrolyte membrane (PEM) fuel cells, the pore network models are often applied. The presented model is a novel approach to further develop these models towards a percolation model that is based on the fiber structure rather than the pore structure. The developed algorithm determines the stable liquid water paths in the gas diffusion layer (GDL) structure and the transitions from the paths to the subsequent paths. The obtained water path network represents the basis for the calculation of the percolation process with low calculation efforts. A good agreement with experimental capillary pressure-saturation curves and synchrotron liquid water visualization data from other literature sources is found. The oxygen diffusivity for the GDL with liquid water saturation at breakthrough reveals that the porosity is not a crucial factor for the limiting current density. An algorithm for condensation is included into the model, which shows that condensing water is redirecting the water path in the GDL, leading to an improved oxygen diffusion by a decreased breakthrough pressure and changed saturation distribution at breakthrough.

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“…A number of visualisation techniques were applied to monitor the water distribution and transport in different parts of PEMFC including fluorescence microscopy [125], Environmental Scanning Electron Microscope (ESEM) [88,126], X-Ray radiography [127][128][129][130][131][132][133], X-Ray tomography [134], neutron radiography [135][136][137], magnetic resonance [138], and video cameras [139][140][141][142][143]. An overview of these experimental techniques can be found in [144,145].…”

Section: Water Distribution and Transportmentioning

confidence: 99%

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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Characteristics of oxygen diffusivity and water distribution by X-ray radiography in microporous media in alternate porous layers of different wettability for moisture control in gas diffusion layer of PEFC

Cited by 37 publications

References 11 publications

Effective gas diffusion coefficient in fibrous materials by mesoscopic modeling

Effective gas diffusion coefficient in fibrous materials by mesoscopic modeling

Modeling the Liquid Water Transport in the Gas Diffusion Layer for Polymer Electrolyte Membrane Fuel Cells Using a Water Path Network

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

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