Membrane electrode assembly structure design

The main advantage of the GDE technique is that the electrode structure is similar to the fuel cell membrane electrode assembly. Therefore, the obtained results may be closer to those tested in a real fuel cell. However, the GDE technique is still rarely used in fuel cell studies due to the complicated design of the electrochemical cell, as well as the instability and poor-repeatability of the results. Furthermore, prior to the electrochemical measurements, the GDE needs to... 

Membrane electrode assemblies (MEAs) are typically five-layer structures, as shown in Figure 10.1. The membrane is located in the center of the assembly and is sandwiched by two catalyst layers. The membrane thickness can be from 25 to 50 pm and, as mentioned in Chapter 10, made of perfluorosulfonic acid (Figure 11.3). The catalyst-coated membranes are platinum on a carbon matrix that is approximately 0.4 mg of platinum per square centimeter the catalyst layer can be as thick as 25 pm [12], The carbon/graphite gas diffusion layers are around 300 pm. Opportunities exist for chemists to improve the design of the gas diffusion layer (GDF) as well as the membrane materials. The gas diffusion layer s ability to control its hydrophobic and hydrophilic characteristics is controlled by chemically treating the material. Typically, these GDFs are made by paper processing techniques [12],... 

The Jet Propulsion Laboratory (JPL) has researched the stated objectives by investigating sputter-deposition (SD) of designed anode and cathode nanostructures of Pt-alloys, and electronic structures and microstructures of sputter-deposited catalyst layers. JPL has used the information derived from these investigations to develop novel catalysts and membrane electrode assemblies (MEAs) that... 

There are multiple transport and reaction steps in a fuel cell. Many of these reaction and transport processes are discussed in other chapters. PEM fuel cell designs have been heuristically derived to achieve high power output. Many proprietary methods of membrane-electrode assemblies have been developed, as well as complex structures of the flow fields, to provide the... 

The structures and components of proton exchange membrane (PEM) fuel cells and the designs of all the components, including the membrane electrode assembly (MEA), single cell, and stack, have been described and discussed in Chapter 2. For a practical PEM fuel cell, every feature of the components, key materials, and cell assembly should be achievable and optimized to achieve high performance. Because a fuel cell is a very complicated device, all the... 

Cheng et al. [19] worked with a PEMFC and described the possibility and efficiency of using a solid polymer electrolyte to replace the liquid electrolyte. Since then, research has focused on the promising development of an AFC based on anion-conducting polymer electrolytes to replace the KOH solution [20-22]. In this new design, the membrane plays the roles of separator and conductive support between the anode and the cathode. This structure, the membrane electrode assembly (MEA), sandwiches the membrane between the two electrodes, which... 

The FR-4 was chosen because it is very stiff, which is necessary for this design. It is important for the electrode grid structure to be as stiff as possible so that it maintains an even contact surface over the membrane surfaces within the assembly, especially when it is tightened with the pressure adjustment screws. 

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