Impact of Cathode Fabrication on Fuel Cell Performance

Tanuma, Toshihiro; Kinoshita, Shinji

doi:10.1149/2.064401jes

Cited by 29 publications

(38 citation statements)

References 27 publications

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“…This result is consistent with the results by Tanuma et al which were obtained by using a single cell with an active area of 25 cm 2 in wet conditions (80 • C, 100%RH). 20 The limiting current densities of the cell using the GDE method are higher than those using the decal transfer method. The differences in the cell voltages of the two types of MEA increase as the cell temperature decreases.…”

Section: Resultsmentioning

confidence: 92%

“…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: 99%

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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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Section: Resultsmentioning

confidence: 92%

Section: F360mentioning

confidence: 99%

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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“…This section investigates the effect of the interfacial structure at the contact between the CL and the MPL on the cell performance using two types of membrane electrode assemblies (MEAs) on the cathode side. These MEAs were experimentally produced by Asahi Glass Co., Ltd. [18,19]: one was manufactured by a conventional decal transfer method which combines -10 -a hydrophobic MPL coated GDL and a CL by hot-pressing, and the other was made by a gas diffusion electrode (GDE) method which directly coats a hydrophobic MPL surface with catalyst ink to form a CL at the cathode side (the decal transfer method was applied at the anode side) [18,19]. Because of the direct coating of the MPL with the CL, it may be assumed that there is an interfacial structure without large gaps between the CL and the MPL with the GDE.…”

Section: Effect Of Interfacial Structure At the CL And Mpl Contactmentioning

confidence: 99%

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

Aoyama

Kadowaki

et al. 2015

Journal of Power Sources

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In polymer electrolyte membrane fuel cells, a gas diffusion layer (GDL) with a micro-porous layer (MPL) gives better anti-flooding performance than GDLs without an MPL. To investigate the function and mechanism of the MPL to suppress water flooding, the liquid water distribution at the cathode catalyst layer (CL) surface are observed by a freezing method; in the method liquid water is immobilized in ice form by rapid freezing, followed by disassembling the cell for observations. The ice covered area is quantified by image processing and cells with and without an MPL are compared. The results show that the MPL suppresses water accumulation at the interface due to smaller pore size and finer contact with the CL, and this results in less water flooding. Investigation of ice formed after −10 °C cold start shutdowns and the temporary performance deterioration at ordinary temperatures also indicates a significant influence of the liquid water accumulating at the interface. The importance of the fine contact between CL and MPL, the relative absence of gaps, is demonstrated by a gas diffusion electrode (GDE) which is directly coated with catalyst ink on the surface of the MPL achieving finer contact of the layers. Highlights• Liquid water distribution at the cathode catalyst layer (CL) surface is observed.• Performance deteriorates due to the liquid water accumulated on the CL surface.• The MPL reduces liquid water accumulation between the CL and the MPL.• Cold startup induces much water accumulation and temporary performance deterioration.• A gas diffusion electrode with fine CL to MPL contact mitigates the flooding.

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“…20 As a reference GDL for the anode, a commercially available GDL (X0086 IX92 CX320, hydrophobically treated GDL with an MPL, Freudenberg-NOK) was used.…”

Section: Methodsmentioning

confidence: 99%

“…16 Departing from the conventional design of MPLs using PTFE, we conceived the idea of hydrophilic MPLs consisting of carbon fiber and ionomer, and reported that the MEA employing a hydrophilic MPL on the cathode side exhibited much better performance in a wide range of pressure and humidity than that using a hydrophobic MPL. [17][18][19][20] The hydrophilic MPL consists of ionomer and vapor-grown carbon fiber with a fiber diameter of 150 nm, and in addition to that, thorough consideration to the surface nature (hydrophobicity/hydrophilicity) of the MPL was given in our previous paper. 18 We applied our technique of preparing a carbon fiber dispersion to the fabrication of MPLs using carbon particles and carbon fibers with various fiber diameters.…”

mentioning

confidence: 99%

Effect of Properties of Hydrophilic Microporous Layer (MPL) on PEFC Performance

Tanuma

Kawamoto

Kinoshita

2017

J. Electrochem. Soc.

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For better water management in polymer electrolyte fuel cells (PEFCs), microporous layers (MPLs) are generally used. In this paper, hydrophilic MPLs having various pore volumes and diameters were prepared using a range of carbon materials, and the effect of the MPL on the membrane electrode assembly (MEA) performance was investigated under dry and wet conditions. Under the dry condition (80 • C, 30%RH), the MEA employing an MPL with a larger median pore diameter showed higher cell voltage, suggesting that the MPL with a larger pore diameter has better gas diffusivity, leading to better MEA performance. Under the wet condition (80 • C, 100%RH), it was confirmed that pore volume of the MPL has a significant impact on the MEA performance and that the hydrophilic MPL with a large pore volume was effective in reducing water flooding in the cathode catalyst layer. When used in an MPL, VGCF-H (carbon fiber with a fiber diameter of 150 nm) gives the largest pore diameter and pore volume. This MEA with a hydrophilic MPL (made of VGCF-H and ionomer) showed the best MEA performance under both dry and wet operating conditions.

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Impact of Cathode Fabrication on Fuel Cell Performance

Cited by 29 publications

References 27 publications

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

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

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

Effect of Properties of Hydrophilic Microporous Layer (MPL) on PEFC Performance

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