Effective transport coefficients in PEM fuel cell catalyst and gas diffusion layers: Beyond Bruggeman approximation

Das, Prodip K.; Li, Xianguo; Liu, Zhong‐Sheng

doi:10.1016/j.apenergy.2009.05.006

Cited by 149 publications

(103 citation statements)

References 35 publications

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“…23 This trend was explained by a decrease in porosity with increasing compression and was confirmed by ex-situ measurements which yielded comparable results in diffusivity and permeability. 4,22,[24][25][26] The data from Baker et al 23 would result in a slope for the respective recalculated values of R T,dry ≈ 0.005 s cm −1 per % of C GDL (fitted between C GDL of 5% and 30%, at higher compression stagnation of R T,dry ), which is half of the value observed in this study and which may be related to the different microstructure of the Toray paper used by Baker et al 23 compared to the GDL 25BC material used in our study (e.g., the use of untreated Toray paper vs. the hydrophobically treated GDL 25BC, differences in porosity) and the absence of an MPL for the Toray paper.…”

Section: Resultsmentioning

confidence: 99%

“…This in turn results in a lower effective diffusivity and a higher oxygen transport resistance at dry conditions. [22][23][24][25][26] Thus, there exists an optimum compression, taking into account the electrical and mass transport losses. 27,28 Additionally, in a fuel cell assembly the influence of the land and channel geometry has to be taken into account, which creates a heterogeneity of material properties.…”

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confidence: 99%

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Influence of the Gas Diffusion Layer Compression on the Oxygen Transport in PEM Fuel Cells at High Water Saturation Levels

Simon

Hasché

Gasteiger

2017

J. Electrochem. Soc.

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The impact of the gas diffusion layer (GDL) compression on the oxygen transport is investigated in single cell assemblies at 50°C, RH = 77%, 200 kPaabs and under differential flow conditions. For this, the oxygen transport resistance at low and high current densities is determined by limiting current density measurements at various oxygen concentrations for GDLs with and without microporous layer (MPL). At small current densities (≤0.4 A cm−2), where no liquid water in the GDL/MPL is present, a linear increase of oxygen transport resistance with GDL compression is observed, with the GDL without MPL exhibiting a significantly lower transport resistance. For low compressions of ≈8%, we find that the oxygen transport resistance for the GDL with MPL is increasing disproportionately high in the high current density region (>1.5 A cm−2), where water condensation in the porous media takes place. A similar trend is observed for a GDL without MPL at a typical compression of 22%. Based on these results, we hypothesize that a developing liquid water film is hindering the oxygen diffusion at the interface between MPL and cathode, analogous to what is known to be formed on the cathode surface for GDLs without MPL.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Influence of the Gas Diffusion Layer Compression on the Oxygen Transport in PEM Fuel Cells at High Water Saturation Levels

Simon

Hasché

Gasteiger

2017

J. Electrochem. Soc.

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“…(6) of porous structures in batteries [30][31][32][33][34] and proton exchange membrane (PEM) fuel cells. [35][36][37][38][39][40][41][42][43][44] Moreover, it has been implemented as a standard addition to predicting microstructures in electrochemistry models, such as in the COMSOL Multiphysics modelling software (COMSOL, Inc.). 23 However, predictions given by the Bruggeman correlation are not always consistent with experimental results.…”

Section: Porosity-tortuosity Relationshipsmentioning

confidence: 99%

Tortuosity in electrochemical devices: a review of calculation approaches

Tjaden

Brett

Shearing

2016

International Materials Reviews

192

188

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The tortuosity of a structure plays a vital role in the transport of mass and charge in electrochemical devices. Concentration polarisation losses at high current densities are caused by mass transport limitations and are thus a function of microstructural characteristics. As tortuosity is notoriously difficult to ascertain, a wide and diverse range of methods has been developed to extract the tortuosity of a structure. These methods differ significantly in terms of calculation approach and data preparation techniques. Here, we review tortuosity calculation procedures applied in the field of electrochemical devices to better understand the resulting values presented in the literature. Visible differences between calculation methods are observed, especially when using porosity-tortuosity relationships and when comparing geometric and flux based tortuosity calculation approaches.

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“…Some theoretical formulas describing the relation between the EGDC and porosity are available [2][3][4][5][6][7][8]. Among the formulas, the Bruggeman's formula [4] is very frequently used for calculating the EGDC of a CCL.…”

Section: Introductionmentioning

confidence: 99%

Measurement of effective gas diffusion coefficients of catalyst layers of PEM fuel cells with a Loschmidt diffusion cell

Shen

Zhou

Astrath

et al. 2011

Journal of Power Sources

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In this work, using an in-house made Loschmidt diffusion cell, we measure the effective coefficient of dry gas (O 2 -N 2 ) diffusion in cathode catalyst layers of PEM fuel cells at 25 • C and 1 atmosphere. The thicknesses of the catalyst layers under investigation are from 6 to 29 m. Each catalyst layer is deposited on an Al 2 O 3 membrane substrate by an automated spray coater. Diffusion signal processing procedure is developed to deduce the effective diffusion coefficient, which is found to be (1.47 ± 0.05) × 10 −7 m 2 s −1 for the catalyst layers. Porosity and pore size distribution of the catalyst layers are also measured using Hg porosimetry. The diffusion resistance of the interface between the catalyst layer and the substrate is found to be negligible. The experimental results show that the O 2 -N 2 diffusion in the catalyst layers is dominated by the Knudsen effect. Crown

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Effective transport coefficients in PEM fuel cell catalyst and gas diffusion layers: Beyond Bruggeman approximation

Cited by 149 publications

References 35 publications

Influence of the Gas Diffusion Layer Compression on the Oxygen Transport in PEM Fuel Cells at High Water Saturation Levels

Influence of the Gas Diffusion Layer Compression on the Oxygen Transport in PEM Fuel Cells at High Water Saturation Levels

Tortuosity in electrochemical devices: a review of calculation approaches

Measurement of effective gas diffusion coefficients of catalyst layers of PEM fuel cells with a Loschmidt diffusion cell

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