Synchrotron X-ray Radiography as a Highly Precise and Accurate Method for Measuring the Spatial Distribution of Liquid Water in Operating Polymer Electrolyte Membrane Fuel Cells

Synchrotron X-ray radiography, due to its high temporal and spatial resolutions, provides a valuable means for understanding thein operandowater transport behaviour in polymer electrolyte membrane fuel cells. The purpose of this study is to address the specific artefact of imaging sample movement, which poses a significant challenge to synchrotron-based imaging for fuel cell diagnostics. Specifically, the impact of the micrometer-scale movement of the sample was determined, and a correction methodology was developed. At a photon energy level of 20 keV, a maximum movement of 7.5 µm resulted in a false water thickness of 0.93 cm (9% higher than the maximum amount of water that the experimental apparatus could physically contain). This artefact was corrected by image translations based on the relationship between the false water thickness value and the distance moved by the sample. The implementation of this correction method led to a significant reduction in false water thickness (to ∼0.04 cm). Furthermore, to account for inaccuracies in pixel intensities due to the scattering effect and higher harmonics, a calibration technique was introduced for the liquid water X-ray attenuation coefficient, which was found to be 0.657 ± 0.023 cm−1at 20 keV. The work presented in this paper provides valuable tools for artefact compensation and accuracy improvements for dynamic synchrotron X-ray imaging of fuel cells.

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Woven gas diffusion layers for polymer electrolyte membrane fuel cells: Liquid water transport and conductivity trade-offs

Journal of Power Sources ◽

10.1016/j.jpowsour.2018.09.076 ◽

2018 ◽

Vol 403 ◽

pp. 192-198 ◽

Cited By ~ 11

Author(s):

S. Hasanpour ◽

M. Ahadi ◽

M. Bahrami ◽

N. Djilali ◽

M. Akbari

Keyword(s):

Fuel Cells ◽

Polymer Electrolyte ◽

Liquid Water ◽

Polymer Electrolyte Membrane ◽

Gas Diffusion ◽

Gas Diffusion Layers ◽

Electrolyte Membrane ◽

Diffusion Layers ◽

Trade Offs ◽

Liquid Water Transport

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Identifying in operando changes in membrane hydration in polymer electrolyte membrane fuel cells using synchrotron X-ray radiography

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2018.03.224 ◽

2018 ◽

Vol 43 (20) ◽

pp. 9757-9769 ◽

Cited By ~ 7

Author(s):

R. Banerjee ◽

N. Ge ◽

C. Han ◽

J. Lee ◽

M.G. George ◽

...

Keyword(s):

Fuel Cells ◽

Polymer Electrolyte ◽

Polymer Electrolyte Membrane ◽

X Ray ◽

Electrolyte Membrane ◽

In Operando

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Effect of gas diffusion layer thickness on liquid water transport characteristics in polymer electrolyte membrane fuel cells

Journal of Power Sources ◽

10.1016/j.jpowsour.2020.228578 ◽

2020 ◽

Vol 475 ◽

pp. 228578 ◽

Cited By ~ 1

Author(s):

Dong Hyup Jeon

Keyword(s):

Fuel Cells ◽

Polymer Electrolyte ◽

Layer Thickness ◽

Water Transport ◽

Liquid Water ◽

Polymer Electrolyte Membrane ◽

Gas Diffusion ◽

Diffusion Layer Thickness ◽

Electrolyte Membrane ◽

Liquid Water Transport

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Pore network modeling of liquid water and oxygen transport through the porosity-graded bilayer gas diffusion layer of polymer electrolyte membrane fuel cells

Electrochimica Acta ◽

10.1016/j.electacta.2019.03.115 ◽

2019 ◽

Vol 306 ◽

pp. 264-276 ◽

Cited By ~ 10

Author(s):

Ninghua Zhan ◽

Wei Wu ◽

Shuangfeng Wang

Keyword(s):

Fuel Cells ◽

Polymer Electrolyte ◽

Diffusion Layer ◽

Oxygen Transport ◽

Liquid Water ◽

Network Modeling ◽

Polymer Electrolyte Membrane ◽

Gas Diffusion Layer ◽

Gas Diffusion ◽

Electrolyte Membrane

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The Impacts of Microporous Layer Degradation on Liquid Water Distributions in Polymer Electrolyte Membrane Fuel Cells Using Synchrotron Imaging

ECS Transactions ◽

10.1149/08008.0155ecst ◽

2017 ◽

Vol 80 (8) ◽

pp. 155-164

Author(s):

Hang Liu ◽

Michael G George ◽

Roswitha Zeis ◽

Matthias Messerschmidt ◽

Joachim Scholta ◽

...

Keyword(s):

Fuel Cells ◽

Polymer Electrolyte ◽

Liquid Water ◽

Polymer Electrolyte Membrane ◽

Microporous Layer ◽

Electrolyte Membrane ◽

Synchrotron Imaging

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Electronic Structures of Non-Pt Carbon Alloy Catalysts for Polymer Electrolyte Membrane Fuel Cells Revealed by Synchrotron Radiation Analyses

MRS Proceedings ◽

10.1557/opl.2011.437 ◽

2011 ◽

Vol 1318 ◽

Cited By ~ 1

Author(s):

Masaharu Oshima ◽

Hideharu Niwa ◽

Makoto Saito ◽

Masaki. Kobayashi ◽

Koji Horiba ◽

...

Keyword(s):

Fuel Cells ◽

Polymer Electrolyte ◽

Active Site ◽

Electronic Structures ◽

Polymer Electrolyte Membrane ◽

Pt Catalysts ◽

X Ray ◽

Electrolyte Membrane ◽

X Ray Absorption ◽

Alloy Catalysts

ABSTRACTThe oxygen reduction reaction (ORR) mechanism of non-Pt catalysts was elucidated by investigating electronic structures of carbon alloy catalysts (CACs) for polymer electrolyte membrane fuel cells (PEMFC). For metal phthalocyanine-based carbon alloy catalysts with 1-2% of nitrogen and less than 0.1% of Co or Fe, photoelectron spectroscopy, X-ray absorption spectroscopy (XAS), and X-ray Absorption Fine Structure (XAFS) have revealed that Co or Fe metal sites are not the ORR active site, whereas the carbon atoms adjacent to graphitic nitrogens at a zigzag edge of graphite may act as the ORR active site, which is in good agreement with first principles calculations. These studies have also revealed that the zigzag edges, detected as a XAS shoulder component, are well evolved for catalysts pyrolyzed at 600°C, which show the maximum ORR activity. Based on these analyses, we have realized significantly improved carbon alloy based ORR performance, up to about 70 % of that with Pt catalysts. Further, to analyze the electronic structure of CACs during operation, we constructed a new in situ soft X-ray emission spectroscopy system with very high energy resolution (ΔE) of 120 meV at 640 eV at the University of Tokyo beamline BL07LSU in SPring-8.

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