Pore network modeling of a microporous layer for polymer electrolyte fuel cells under wet conditions

Nakajima, Hironori; Iwasaki, Satoshi; Kitahara, Tatsumi

doi:10.1016/j.jpowsour.2023.232677

Cited by 7 publications

(4 citation statements)

References 24 publications

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“…The increase in water permeability with increasing of the MPL and the increase in liquid water saturation. Thereby liquid water transport paths increase based on the water, air, and capillary pressure balance for each pore diameter according to the Young-Laplace formula (9).…”

Section: Resultsmentioning

confidence: 99%

“…Pressurized water in the liquid water channel is injected in an in-plane direction through the MPL to the catalyst layer, and the produced oxygen gas is transported in a throughplane direction through the MPL and discharged into the oxygen gas channel (8). Pressurized liquid water and oxygen gas balance with the capillary pressures in the pores of the hydrophobic MPL (9), so that the gas-liquid separation is internally established. No significant liquid water leakage has been detected into the oxygen gas flow channels.…”

Section: Introductionmentioning

confidence: 99%

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Liquid Water Permeability in a Hydrophobic Microporous Layer for the Anode Interdigitated Flow Field of a Gas-Liquid Separating Polymer Electrolyte Membrane Water Electrolyzer

Kubota,

Nakajima,

Sato

et al. 2023

ECS Trans.

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A novel interdigitated flow field for polymer electrolyte membrane water electrolyzers composed of oxygen exhaust channels apart from liquid water feed channels has been developed for ground and space applications. This design can internally separate oxygen gas and liquid water between the flow channels, dispensing with water circulators for bubble removal and external separators with natural or centrifugal buoyancy. In this electrolyzer, pressurized liquid water is injected in the in-plane direction from the water channels to the catalyst layer through the hydrophobic microporous layer (MPL) of the anode porous transport layer. The produced oxygen gas is discharged in the through-plane direction of the MPL, taking advantage of the capillary pressure in the MPL. This study conducted liquid water permeability tests on the MPL with pressurized water. We find gradual permeability decreases with time for different liquid water pressures. The permeability will be a useful parameter for the optimal structural designs of this electrolyzer.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Liquid Water Permeability in a Hydrophobic Microporous Layer for the Anode Interdigitated Flow Field of a Gas-Liquid Separating Polymer Electrolyte Membrane Water Electrolyzer

Kubota,

Nakajima,

Sato

et al. 2023

ECS Trans.

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“…Grunewald and co-authors presented a lattice Boltzmann method model applied to a cathode catalyst layer (CCL), which combines tomography data and mesoscale modeling techniques, to improve the knowledge of the transport mechanisms of the oxygen in the catalyst layer [95]. In an article by Pournemat, a voxel-based Montecarlo model describes the strict relationship between the wettability and pore size distribution on the water distribution within the gas diffusion layer (GDL) and the CCL [96], while Nakajima used FIB-SEM tomography to model the pore network of their hydrophobic microporous layers to evaluate the convective air permeability and oxygen diffusivity [97]. A similar work has been published by Maloum et al, who used the data collected from X-ray and FIB tomography to construct an innovative numerical computation for the evaluation of the microporous layer in a fibrous GDL [98].…”

Section: Fuel Cellsmentioning

confidence: 99%

Advances in Focused Ion Beam Tomography for Three-Dimensional Characterization in Materials Science

Mura,

Cognigni,

Ferroni

et al. 2023

Materials

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Over the years, FIB-SEM tomography has become an extremely important technique for the three-dimensional reconstruction of microscopic structures with nanometric resolution. This paper describes in detail the steps required to perform this analysis, from the experimental setup to the data analysis and final reconstruction. To demonstrate the versatility of the technique, a comprehensive list of applications is also summarized, ranging from batteries to shale rocks and even some types of soft materials. Moreover, the continuous technological development, such as the introduction of the latest models of plasma and cryo-FIB, can open the way towards the analysis with this technique of a large class of soft materials, while the introduction of new machine learning and deep learning systems will not only improve the resolution and the quality of the final data, but also expand the degree of automation and efficiency in the dataset handling. These future developments, combined with a technique that is already reliable and widely used in various fields of research, are certain to become a routine tool in electron microscopy and material characterization.

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“…Pressurized water can also provide an advantage to reduce the humidity of the product oxygen for practical use under atmospheric pressure by producing pressurized oxygen. The MPL provides water support force with capillary pressure (14)(15)(16), so that internal gas-liquid separation is established. Thus water circulators for bubble removal and conveyance in a cell by drag force with liquid water flow(17) used for conventional water electrolyzers can be dispensed with.…”

Section: Introductionmentioning

confidence: 99%

Water Transport Modeling in a Microporous Layer for a Polymer Electrolyte Membrane Water Electrolyzer Having a Gas-Liquid Separating Interdigitated Flow Field

Nakajima,

Ekström,

Shima

et al. 2023

ECS Trans.

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A new interdigitated flow field design for polymer electrolyte membrane electrolyzers has been developed for ground and space applications. It internally separates oxygen and liquid water, eliminating the water circulators to remove the bubbles and external gas-liquid separators with buoyancy. The capillary pressure in the hydrophobic microporous layer(MPL) of the anode porous transport layer enables the internal separation of oxygen gas and pressurized liquid water. A finite element model (COM-SOL Multiphysics) simulates water transport in the MPL. Electrochemical impedance spectra determine the electrochemical kinetic parameters for the model. The model accounts for the oxygen bubble coverage of the CL, liquid water saturation in the MPL, and the current ratio between liquid water and water vapor at the MPL-CL interface. The vapor from liquid water in the MPL mixes with oxygen for diffusion. The water evaporation rate based on liquid water saturation in the MPL is introduced.

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Pore network modeling of a microporous layer for polymer electrolyte fuel cells under wet conditions

Cited by 7 publications

References 24 publications

Liquid Water Permeability in a Hydrophobic Microporous Layer for the Anode Interdigitated Flow Field of a Gas-Liquid Separating Polymer Electrolyte Membrane Water Electrolyzer

Liquid Water Permeability in a Hydrophobic Microporous Layer for the Anode Interdigitated Flow Field of a Gas-Liquid Separating Polymer Electrolyte Membrane Water Electrolyzer

Advances in Focused Ion Beam Tomography for Three-Dimensional Characterization in Materials Science

Water Transport Modeling in a Microporous Layer for a Polymer Electrolyte Membrane Water Electrolyzer Having a Gas-Liquid Separating Interdigitated Flow Field

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