Compress effects on porosity, gas-phase tortuosity, and gas permeability in a simulated PEM gas diffusion layer

2015 ◽  
Vol 39 (11) ◽  
pp. 1528-1536 ◽  
Author(s):  
Mayken Espinoza ◽  
Martin Andersson ◽  
Jinliang Yuan ◽  
Bengt Sundén
Keyword(s):  
Gas Phase ◽  
Diffusion Layer ◽  
Gas Permeability ◽  
Gas Diffusion Layer ◽  
Gas Diffusion

Effect of Carbon Fiber Felt Pretreatment on Properties of Carbon Fiber Paper

2011 ◽  
Vol 194-196 ◽  
pp. 1620-1623 ◽  
Author(s):  
Xue Jun Zhang ◽  
Hao Pei ◽  
Zeng Min Shen
Keyword(s):  
Fuel Cell ◽  
Carbon Fiber ◽  
Diffusion Layer ◽  
Gas Permeability ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Carbon Fiber Felt ◽  
Fuel Cell Electrode ◽  
Carbon Fiber Paper ◽  
Cell Electrode

Gas diffusion layer is a very important component in fuel cell, and carbon fiber paper is widely used as substrate of gas diffusion layer. This paper has developed one way to produce carbon fiber paper from carbon fiber felt with or without pretreatment. The properties and microstructure of carbon fiber paper were also stdied. The results show that the pretreatment of carbon fiber felt is helpful to prepare carbon fiber paper with good properties. The content of carbon derived from resin during pretreatment has effects on density, thickness, porosity, gas permeability, porosity and tensile streagth of carbon fiber paper. Carbon fiber paper made from carbon fiber felt with pretreatment has better interface adhension than that of carbon fiber paper made from carbon fiber felt without pretreatment. Carbon fiber paper was produced with thickness of 0.28mm, density of 0.43g/cm3, porosity of 77%, gas permeability of 2500 mL•mm/(cm2•hr•mmAq), specific resistance of 0.017Ω•cm and tensile strength of 18MPa, which is a promising materials for fuel cell electrode.

Characterization of Gas Diffusion Electrodes for Polymer Electrolyte Fuel Cells

2010 ◽  
Vol 7 (4) ◽  
Author(s):  
A. Pozio ◽  
A. Cemmi ◽  
M. Carewska ◽  
C. Paoletti ◽  
F. Zaza
Keyword(s):  
Fuel Cells ◽  
Polymer Electrolyte ◽  
Diffusion Layer ◽  
Gas Permeability ◽  
Current Collector ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Polymer Electrolyte Fuel Cells ◽  
Metal Catalyst ◽  
Gas Diffusion Electrodes

Gas diffusion electrodes (GDEs), applied in polymer electrolyte fuel cells, are composed of a multilayer structure containing porous carbon materials and noble metal catalyst. Gas diffusion layer (GDL), a GDE component, consists of a thin layer of carbon black mixed with an organic binder, frequently polytetrafluoroethylene, which is coated onto a sheet of macroporous carbon backing cloth or paper. GDL serves as a current collector that allows ready access of fuel and oxidant to the anode and the cathode catalyst surfaces, respectively. In this work, a complete GDL state-of-the-art is first presented. Then, the effects of different fabrication methods and composition of gas diffusion layer are investigated and discussed in the light of gas permeability, thermal analysis, morphology, and electrical resistance. Besides, performances in H2/air fed cell at 50°C in different humidity conditions were discussed, and a comparison with own products and commercial GDLs was carried out. It was found that the different preparation methods influence the GDL properties, allowing the most suitable choice depending on the cell humidity conditions.

Effects of Assembly Pressure on the Gas Diffusion Layer and Performance of a PEM Fuel Cell

2011 ◽  
Vol 110-116 ◽  
pp. 48-52 ◽  
Author(s):  
Hao Ming Chang ◽  
Min Hsing Chang
Keyword(s):  
Fuel Cell ◽  
Diffusion Layer ◽  
Gas Permeability ◽  
Gas Diffusion Layer ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Cell Performance ◽  
Carbon Paper ◽  
Membrane Electrode ◽  
Clamping Pressure

Assembly pressure plays an important role in the factors affecting the performance of a PEM fuel cell. An insufficient clamping pressure may cause large contact resistance and thus lower the cell performance. On the other hand, over-clamping may reduce the porosity and permeability of the gas diffusion layer (GDL) and also result in poor cell performance. Therefore, it is very important to determine the proper assembly pressure for obtaining optimal performance. In this study, we design a special test fixture to evaluate the effect of assembly pressure on the performance of a PEM fuel cell. Without disassembling the fuel cell, the clamping pressure can be adjusted in situ to measure the cell performance directly and precisely. The unique single cell design eliminates the influence of gasket around the membrane electrode assembly (MEA) and makes it possible to estimate the compression effect of GDL independently. Three different types of carbon paper are used in the experiments as the GDLs. The variations of water contact angle, gas permeability, and in-plane electrical resistivity with the assembly pressure are also measured to explore the effects of assembly pressure on these physical properties. The results show that an optimal assembly pressure is always observed in each case, indicating an adequate compression on GDL is quite necessary for fuel cells.

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