Impact of micro-porous layer on liquid water distribution at the catalyst layer interface and cell performance in a polymer electrolyte membrane fuel cell

Tabe, Yutaka; Aoyama, Yusuke; Kadowaki, Kazumasa; Suzuki, Kengo; Chikahisa, Takemi

doi:10.1016/j.jpowsour.2015.04.095

Cited by 44 publications

(29 citation statements)

References 19 publications

(39 reference statements)

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“…This suggests that the MPL can prevent water accumulation in the flow field land area, where high contact pressure is observed; at the same time, however, at the decreased contact pressure in the channel regions, liquid water can accumulate in gaps between the MPL and the cathode electrode layer. 7,14,15,53 Finally, this is also supported by the calculation of the water storage capacities at the cathode/MPL interface based on surface roughness measurements: Swamy et al predict a three times higher maximum water content inside interfacial gaps without applied compression in the flow field channels compared to 1.5 MPa, which corresponds to a typical flow field land compression pressure. 14 The here presented effect of high oxygen mass transport resistances at very low compressions is not only relevant in case of inhomogeneous compression of the diffusion medium, e.g., if the cells of a stack are locally under compressed.…”

Section: F598mentioning

confidence: 71%

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: F598mentioning

confidence: 71%

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 authors also observed the in-plane (direction parallel to the MEA surface) water distribution on the CL surface to understand the mechanism of the MPL suppression of water flooding. 19 The results indicated that water accumulation at the CL surface increases with increasing current density, and the addition of the MPL could suppress water accumulation at the CL surface as a result of the finer contact with the CL.…”

Section: F360mentioning

confidence: 90%

“…20 The authors also investigated the effect of the MPL/CL interface, and the results showed that an MEA made by the GDE method increases the cell voltage under wet conditions over those of an MEA made with the decal method at specific temperature conditions. 19 These results suggested that a smooth MPL/CL interface without gaps could be expected to prevent water accumulation and so improve cell performance.…”

Section: F360mentioning

confidence: 92%

Water Transport and PEFC Performance with Different Interface Structure between Micro-Porous Layer and Catalyst Layer

Aoyama

Suzuki

Tabe

et al. 2016

J. Electrochem. Soc.

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For interfaces between micro-porous layers (MPL) and catalyst layers (CL) made by the gas diffusion electrode (GDE) method, a seamless interface without gaps, shows better performance than that of cells with an interface made by the decal transfer method. With the decal transfer method, the MPL is simply hot-pressed to the CL-membrane assembly. This study investigates the effect of interface structure on cell performance and water transport in the MPL. Water distribution in cross sections of multiple layers were observed by a freezing method, where the cell is cooled below freezing temperature in short time and the water was observed in ice form by Cryo-SEM. The results show that a membrane electrode assembly (MEA) using the GDE method improves cell performance at high current densities. Direct observations by the freezing method and cryo-SEM show that there is no water accumulation at the MPL/CL interface made by the GDE method, while water accumulates at the interface made by the decal method. Other observations show that the water amount inside the MPL increases similarly in the two types of MEA when lowering the temperature, and the difference between the two types of MEA was only the water amount in the interface. Polymer electrolyte fuel cells (PEFCs) are promising power sources for next generation vehicles, motorcycles, and residential cogeneration systems (the so-called combined heat and power; CHP). However, there is considerable potential for improvements in the performance for the PEFC to become practical in many other applications. Water flooding, the blockage of the gas supply to the reaction area by accumulation of water, is one of the major issues with the PEFC, as cell performance deteriorates significantly under high current density conditions. Micro-porous layers (MPLs), typically consisting of carbon black and a hydrophobic polymer, have been demonstrated to be an important component in improving the water management of the PEFC.The effect of a hydrophobic MPL on the water transport mechanism in the cell has been investigated by computational and experimental studies, and these studies have suggested that the MPL removes produced water from the reaction area.1-5 Weber et al. and Pasaogullari et al. reported that the MPL reduces the amount of water passing through the cathode side of the gas diffusion layer (GDL) by increasing the water flow from cathode to anode.1,2 Gostick et al. and Lu et al. suggested that cracks in the MPL are the pathways of the water discharge, and that this results in reductions in the water saturation in the GDL.3,4 Owejan et al. investigated water transport in the MPL by measuring the performance of cells with various types of MPL, and proposed that the MPL prevents the water in the GDL from contacting with and forming a water film on the catalyst layer (CL) surface.5 They also investigated the water vapor transport capacity through the MPL driven by the saturation pressure gradient in the cathode diffusion layer due to the temperature gradient, and demonstrated that ...

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“…It was shown that voids may be formed in CL, GDL or CL/MPL/ GDL interfaces under serious carbon corrosion conditions [52]. Liquid water may accumulate in such voids and delaminated locations and increase mass transport resistance [53]. During the recovery procedure, membrane and other components experience frequent swelling and contraction.…”

Section: Electrochemical Impedance Spectroscopymentioning

confidence: 99%

Recovery mechanisms in proton exchange membrane fuel cells after accelerated stress tests

Zhang

Guo

Liu

2015

Journal of Power Sources

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Impact of micro-porous layer on liquid water distribution at the catalyst layer interface and cell performance in a polymer electrolyte membrane fuel cell

Cited by 44 publications

References 19 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

Water Transport and PEFC Performance with Different Interface Structure between Micro-Porous Layer and Catalyst Layer

Recovery mechanisms in proton exchange membrane fuel cells after accelerated stress tests

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