Effective diffusivity of polymer electrolyte fuel cell gas diffusion layers: An overview and numerical study

Ismail, M.S.; Ingham, D.B.; Hughes, Kevin J.; Ma, Lin; Pourkashanian, Mohamed

doi:10.1016/j.ijhydene.2015.06.073

Cited by 48 publications

(30 citation statements)

References 58 publications

(109 reference statements)

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“…To efficiently perform the above functions, the GDL is usually wet-proofed [3][4][5][6][7]. Further, it is normally coated with the so-called micro-porous layer (MPL) on the side facing the catalyst layer in order to enhance the electrical contact with the catalyst layer and properly handle the liquid water emerging from the cathode catalyst layer [1][2][9][10]. The MPL is a mixture that typically consists of carbon black and PTFE particles [1,11].…”

Section: Introductionmentioning

confidence: 99%

The effects of the composition of microporous layers on the permeability of gas diffusion layers used in polymer electrolyte fuel cells

Orogbemi

Ingham

Ismail

et al. 2016

International Journal of Hydrogen Energy

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Section: Introductionmentioning

confidence: 99%

The effects of the composition of microporous layers on the permeability of gas diffusion layers used in polymer electrolyte fuel cells

Orogbemi

Ingham

Ismail

et al. 2016

International Journal of Hydrogen Energy

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“…The Bruggeman approximation was found to significantly over-predict diffusion in the GDL [28]. Therefore, an alternative formula, which reasonably fits the relevant experimental data reported in the literature, was used to calculate the effective diffusivity of the GDL [28]:…”

Section: [Insert Fig 2] Pefc Cathode Modelmentioning

confidence: 99%

“…5 and Table 2] 3. Results and discussion The derived expression for the effectiveness factor r E of the spherical agglomerate is given as follows [28,40]:…”

Section: Couplingmentioning

confidence: 99%

“…On the hand, the agglomerate models assume that the catalyst layer is made up of uniformly distributed isolated agglomerates which consist of a uniform mixture of the ionomer, carbon and platinum; see for example [8,. Typically, these agglomerates are assumed to be spherical and covered by a thin ionomer film [28]. The agglomerate models are more realistic than the homogenous models as they (i) account for the dissolution of oxygen into the ionomer phase, and (ii) capture, to a certain extent, the effects of the microstructure of the catalyst agglomerates.…”

Section: Introductionmentioning

confidence: 99%

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Effects of catalyst agglomerate shape in polymer electrolyte fuel cells investigated by a multi-scale modelling framework

Ismail

Ingham

et al. 2017

Energy

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A multi-scale modelling framework is developed for the PEFC cathode electrode. Unlike the conventional agglomerate model, the effects of the microstructure of the agglomerate are numerically coupled to the fuel cell-scale model in this framework. This is performed through solving the agglomerate-scale model first and subsequently extracting and using the data required to generate the performance curves in the fuel cell-scale model. This enables one to freely investigate the structure of the agglomerate without being limited to the only three agglomerate shapes that can be investigated using the conventional agglomerate model: spheres, long cylinders with sealed ends and long slabs with sealed ends. The numerical studies conducted in this work using the developed framework have revealed that the performance of the cathode electrode is highly sensitive to the specific surface area of the agglomerate if the size of the latter is relatively large, i.e. of the order of 1000 nm. Namely, the maximum reported current density has increased by about 60% when changing from the 'large' spherical agglomerate to the 'large' cylindrical agglomerate. Also, it has been shown that a slight change in the structure of the agglomerate may significantly improve the fuel cell performance.

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“…Both parts are treated with poly(tetrafluoroethylene) (PTFE) to obtain specific hydrophobicity needed for fuel cell operation. Flooding of the active catalyst layer (CL), where the reactions take place [4] is avoided by transporting the water away from the reaction layer due to the hydrophobic behavior of GDL [5,6]. Water produced inside the fuel cell can flood the pores of GDL and decrease the gas permeability of the layer promoting fuel starvation [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Modification of gas diffusion layers properties to improve water management

Martı́n

Biswas

Gazdzicki

et al. 2017

Mater Renew Sustain Energy

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In this paper we report an approach to improve water management of commercial GDLs by introducing hydrophobicity patterns. Specifically, line and grid patterns have been created in the MPL side by laser radiation. For an in-depth investigation of these modified GDLs the current density distribution was monitored during fuel cell operation. Additionally, the physical properties of these materials were investigated by a number of ex situ methods such as Fourier transform infrared microscopy, electrochemical impedance spectroscopy and water vapor sorption. Furthermore, a comparison of the physical properties of the patterned GDLs with chemically modified GDLs (treated in H 2 SO 4 and H 2 O 2 ) is provided. Our results show a clearly improved homogeneity of current density distribution of the patterned GDLs compared to untreated GDLs. This observation is likely due to a reduced local hydrophobicity which facilitates water diffusion along the flow field of the fuel cell. However, performance of the fuel cell was not affected by the MPL irradiation.

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Effective diffusivity of polymer electrolyte fuel cell gas diffusion layers: An overview and numerical study

Cited by 48 publications

References 58 publications

The effects of the composition of microporous layers on the permeability of gas diffusion layers used in polymer electrolyte fuel cells

The effects of the composition of microporous layers on the permeability of gas diffusion layers used in polymer electrolyte fuel cells

Effects of catalyst agglomerate shape in polymer electrolyte fuel cells investigated by a multi-scale modelling framework

Modification of gas diffusion layers properties to improve water management

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