Understanding Water Transport in Polymer Electrolyte Fuel Cells Using Coupled Continuum and Pore‐Network Models

Médici, Ezequiel; Zenyuk, Iryna V.; Parkinson, Dilworth Y.; Weber, Adam Z.; Allen, Jeffrey S.

doi:10.1002/fuce.201500213

Cited by 50 publications

(47 citation statements)

References 32 publications

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“…The pore network determines the morphology as a network of pores and throats where the pores act as reservoirs and the connecting throats define the transport pathways. Several groups have worked with pore network models in defining the transport through porous materials, in applications varying from fuel cell diffusion media,, PEM electrolyzers, redox flow battery electrodes, and rock structures . Banerjee et al .…”

Section: Introductionmentioning

confidence: 99%

Comparison of Electrospun Carbon−Carbon Composite and Commercial Felt for Their Activity and Electrolyte Utilization in Vanadium Redox Flow Batteries

et al. 2018

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A low cost highly active carbon−carbon composite fiber felt was produced by electrospinning a mixture of polyacrylonitrile and carbon black powder using poly acrylic acid as a binder for high carbon black loading. The newly designed high‐surface area electrode material showed promising results for use as electrode material for both the negative and positive half‐cell of vanadium redox flow batteries. Battery test results demonstrated promising performance for the electrospun carbon fibers at current densities below 60 mA cm−2, but were less active at higher values. The microstructure of the felt was characterized by X‐ray computed tomography to obtain the porous pathways, which facilitate electrolyte transport. The obtained results will help us to understand the role of porosity in the performance of the battery and to consequently improve the design of the carbon‐filled electrospun material.

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Section: Introductionmentioning

confidence: 99%

Comparison of Electrospun Carbon−Carbon Composite and Commercial Felt for Their Activity and Electrolyte Utilization in Vanadium Redox Flow Batteries

et al. 2018

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“…Due to the low computation cost of PNMs, it has recently been integrated into a full MEA model to predict the local saturation and effective properties of the GDL. 50,51 Despite their usefulness, PNMs do not faithfully represent the pore space, so their predictions of water configurations are only rough estimations. This further reduces the reliability of the gas transport predictions as a function of the local saturation in the GDL.…”

Section: 4mentioning

confidence: 99%

Virtual Liquid Water Intrusion in Fuel Cell Gas Diffusion Media

Sabharwal

Gostick

Secanell

2018

J. Electrochem. Soc.

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A cluster based full morphology (CFM) model is developed to predict liquid water intrusion in GDLs. The CFM model is used to simulate water intrusion into a dry GDL microstructure obtained from μ-CT. Numerical water saturation distributions are compared to experimental μ-CT reconstructions of the same GDL sample at varying saturation levels. A quantitative validation of the CFM model results is then provided by studying the number of voxels in the image that contain water in both the CFM model results and the μ-CT reconstructions. Results reveal that CFM simulations showed 56-95.7% agreement in the liquid water voxels when compared to the μ-CT simulations for saturations in the range of 29-92.3%. Gas transport simulations are then performed on μ-CT and CFM partially saturated GDLs in order to study the validity of the CFM model images to estimate transport properties of partially saturated GDLs. A maximum error of 20% was observed between the predicted effective diffusivities obtained from CFM simulations and those obtained directly from simulations on the μ-CT data for saturations below 40%. Effective diffusivity predictions from the CFM simulations agree well with in-plane effective diffusivities in literature while the through-plane effective diffusivities were underpredicted by a factor of 2.

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“…A pore-network model that has a long history in the study of porous media like soils and rocks 62 has recently been used in understanding water transport in GDL materials. [63][64][65][66][67][68][69] The pore network model maps a complex pore space continuum onto a regular and irregular network of pore bodies and pore throats. Several works have shown that invasion-percolation process, which is a strongly capillary-driven process at the limiting case of zero fluid velocity, may be an important mechanism for water transport in GDL.…”

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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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Understanding Water Transport in Polymer Electrolyte Fuel Cells Using Coupled Continuum and Pore‐Network Models

Cited by 50 publications

References 32 publications

Comparison of Electrospun Carbon−Carbon Composite and Commercial Felt for Their Activity and Electrolyte Utilization in Vanadium Redox Flow Batteries

Comparison of Electrospun Carbon−Carbon Composite and Commercial Felt for Their Activity and Electrolyte Utilization in Vanadium Redox Flow Batteries

Virtual Liquid Water Intrusion in Fuel Cell Gas Diffusion Media

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

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