A review on microstructure reconstruction of PEM fuel cells porous electrodes for pore scale simulation

Shojaeefard, Mohammad Hassan; Molaeimanesh, Gholam Reza; Nazemian, M.; Moqaddari, Mohammad Reza

doi:10.1016/j.ijhydene.2016.08.179

Cited by 101 publications

(46 citation statements)

References 98 publications

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“…In case of the attenuation tomography, resolution limitations, large data volume and difficulty of visualization and analysis are the major drawbacks. FIB/SEM is a destructive and time intensive method, which is not applicable to materials like GDL , . Hence, it is a markedly effective way to use stochastically simulation techniques to reconstruct the microstructure of a heterogeneous material.…”

Section: Introductionmentioning

confidence: 99%

Microstructure Reconstruction and Characterization of the Porous GDLs for PEMFC Based on Fibers Orientation Distribution

2018

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The 3D microstructure of the gas diffusion layers (GDLs) is generated, using a stochastic reconstruction approach. The method uses basic input parameters and fibers orientation distribution and is capable to model carbon fiber and binder phases of all types of carbon fiber GDLs with different structural parameters. Morphological operators of image processing are used to add the binder to the fibrous skeleton in three dimensions. Binder impregnation, pore size distribution and tortuosity factor of the reconstructed GDL are evaluated and compared with literature. Twenty and forty percentages of binder volume fraction are used to reconstruct the microstructure. To further investigate the reliability of our approach, mass transport properties of the reconstructed microstructure, namely absolute permeability, effective diffusivity of the pore space and effective thermal conductivity, are investigated through a finite volume equation solver in AVIZO. Only 4% of discrepancy between the absolute permeability calculation and the value reported by the manufacturer is observed in the through‐plane direction. Finally, in order to show the flexibility of the methodology the microstructure of a commercial Toray GDL is also reconstructed and characterized. The proposed method is proved to be a high‐speed and versatile tool for research and development in the GDL material design.

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Section: Introductionmentioning

confidence: 99%

Microstructure Reconstruction and Characterization of the Porous GDLs for PEMFC Based on Fibers Orientation Distribution

2018

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“…The technique has become a powerful tool to describe morphology and study transport properties inside complex structures like GDLs, MPLs, and catalyst layers. [29][30][31][32][33][34][35][36][37] For example, Epting and Litster 30 used microscale X-ray CT to characterize the morphology of the GDL and provide detail analysis of the local oxygen concentration inside the GDL. Hong et al 31 combined nanoscale X-ray CT with the data from electrochemical diagnostics to enhance the understanding of materials and electrode designs for fuel cell particular under reversal tolerance anode.…”

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confidence: 99%

Micro-Scale Analysis of Liquid Water Breakthrough inside Gas Diffusion Layer for PEMFC Using X-ray Computed Tomography and Lattice Boltzmann Method

Satjaritanun

Weidner

Hirano

et al. 2017

J. Electrochem. Soc.

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The main objective of this work is to predict the breakthrough pressure of liquid water transport through the gas diffusion layer (GDL) and/or micro porous layer (MPL) used in polymer electrolyte membrane fuel cells. The integration of structural GDL and MPL with Lattice Boltzmann Method is primary focused. The numerical predictions are also compared with experimental data. The interaction between liquid phase and different surface treatments of solid structures controls the evolution of liquid water and the change of capillary pressure. The geometries of GDLs and MPLs were obtained by three dimensional reconstructed micro-structure images from both nanometer and micrometer-scaled high spatial resolution X-ray computed tomography (CT). The predictions of water breakthrough pressure agree with the data observed in the experiment. They also reveal that the breakthrough pressure and liquid water evolution inside the GDL samples are different when the wetting properties of GDL and/or MPL are changed. The detailed microporous property can be obtained using high spatial resolution image from nanometer-scaled X-ray CT, a.k.a. Nano X-ray CT. Meanwhile, images from micrometer-scaled X-ray CT, a.k.a. Micro X-ray CT, give proper field of view to cover complete vision of porous materials, including cracks in the MPL. The enhancement of the transport of liquid water and reactant gases in polymer electrolyte membrane fuel cells (PEMFCs) is a critical subject that has been greatly studied due to its critical importance to fuel cell performance at high current densities.1-3 The liquid transport and the concurrent two-phase flow in the gas diffusion layer (GDL) and micro porous layer (MPL) are the most widely studied. In general GDL materials for PEMFCs are made of carbon fiber based cloths and paper. These materials are typically porous to allow for the transport of reactant gases to the catalyst layer as well as transport of condensed water from the catalyst layer. To accelerate the removal of liquid water, GDLs are usually impregnated with non-wetting polymer such as polytetrafluoroethylene (PTFE) to create hydrophobic characteristics. Further, a thin MPL which consists of carbon powder and polymer binders is applied to the GDL side facing the catalyst layer in the membrane electrode assembly (MEA) to further increase cell performance and mechanical stability. The complex structural and chemical heterogeneity of the GDL and MPL make studying the transport of liquid water and obtaining the solution for mass transport losses substantially complicated. 4,5 Many researchers have studied the transport of liquid water through the GDL and MPL in order to develop an understanding of the resistance of reactant gas transport due to water accumulation.6-27 These included the observation of vapor condensation and liquid breakthrough in a GDL using an environmental scanning electron microscope (SEM).13,14 They proposed a treelike transport mechanism in which micro-droplets condensed from vapor agglomerate to form macro-droplets which even...

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“…To simulate the dynamic manner of water droplet in GDL we need to reconstruct the GDL microstructure to obtain the porous geometry. To implement GDL microstructure reconstruction there are two main approaches: imaging combination approach and stochastic reconstruction approach . In the first approach, X‐ray prepares successive GDL tomographic images and subsequently, these images are integrated for the reconstruction of the 3D GDL microstructure.…”

Section: Microstructure Reconstruction Of Gdlmentioning

confidence: 99%

“…GDL, which is made from porous materials like carbon paper, plays a key role in a PEMFC performance via providing mass transfer and conductivity for the CL . Compression and deformation of GDL leads to change of its microstructure and consequently, its diffusivity and conductivity . In fact, in order to guarantee the cell performance the gas stream must be able to eject the droplets emerging on the surface of micro‐porous layer (MPL) from the GDL; and, GDL compression and deformation influences this ejection phenomenon .…”

Section: Introductionmentioning

confidence: 99%

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Effects of Compression on the Removal of Water Droplet from GDLs of PEM Fuel Cells

2019

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Proton-exchange membrane fuel cells (PEMFCs) with a sound potential for employing in the propulsion systems of green vehicles are currently at a high stage of development. However, appropriate water management is crucial for further development of PEMFCs. In the current investigation, the role of gas diffusion layer (GDL) compression and wettability on the removal of a water droplet from different GDLs with dissimilar levels of compression (0%, 15%, 20%, and 25%) and wettability (contact angles of 80°, 105°, and 150°) is inspected by numerous 3D lattice Boltzmann simulations.The results of this study demonstrate that by increasing of compression level, the droplet ejection will be more probable. Besides, for hydrophobic GDLs (i.e., contact angles of 105°a nd 150°) adding compression will help the removal process, regardless of the compression amount. However, for the hydrophilic GDLs (contact angle of 80°) adding compression is not necessarily helpful.

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A review on microstructure reconstruction of PEM fuel cells porous electrodes for pore scale simulation

Cited by 101 publications

References 98 publications

Microstructure Reconstruction and Characterization of the Porous GDLs for PEMFC Based on Fibers Orientation Distribution

Microstructure Reconstruction and Characterization of the Porous GDLs for PEMFC Based on Fibers Orientation Distribution

Micro-Scale Analysis of Liquid Water Breakthrough inside Gas Diffusion Layer for PEMFC Using X-ray Computed Tomography and Lattice Boltzmann Method

Effects of Compression on the Removal of Water Droplet from GDLs of PEM Fuel Cells

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