Hydrogen proton exchange Electrode Assemblies

Molecular-Level Modeling of the Structure and Proton Transport within the Membrane Electrode Assembly of Hydrogen Proton Exchange Membrane Fuel Cells... 

Kim, C. S., Ghun, Y. G., Peck, D. H., and Shin, D. R. A novel process to fabricate membrane electrode assemblies for proton exchange membrane fuel cells. International Journal of Hydrogen Energy 1998 23 1045-1048. 

Previously, the common approach to fabricating membrane and electrode assemblies for proton exchange membrane fuel cells involves hot-pressing a mixture of platinum powder and polytetrafluoroethylene (PTFE) on both sides of a proton exchange membrane. This method has resulted in hydrogen-oxygen fuel cells capable of high power densities. 

Dai W, et al. (2009) A review on water balance in the membrane electrode assembly of proton exchange membrane fuel cells. Int J Hydrogen Energy 34 9461-9478. doi 10.1016/j.ijhydene.2009.09.017... 

The development of commercially viable proton exchange membrane (PEM) fuel cell systems powered by hydrogen or hydrogen-rich reformate faces a significant number of materials and MEA (membrane electrode assembly) design-related performance and durability challenges, which need to be addressed via ... 

A modem FC used in transportation and other applications is shown in Fig. 2. Its key elements are the electrodes, the catalyst, and the proton exchange membrane (PEM) the cell is fueled by hydrogen or methanol at the anode and oxygen or air at the cathode. The membrane electrode assembly (MEA) that is the heart of ECs includes the proton exchange membrane, a polymer modified to include ions, typically sulfonic groups an ionomer In the presence of water, ionomers self-assem-ble into microphase separated domains that allow the movement of in one direction only, from the anode to the cathode. The membrane performance was first demonstrated by Nafion, the ionomer made by DuPont, which consists of a perflu-orinated backbone and pendant chains terminated by sulfonic groups, -SOs . Nafion was the major component in the PEMEC developed by General Electric for... 

A key element of the automotive fuel cell membrane electrode assembly is the proton exchange membrane (PEM), also referred to as the polymer electrolyte membrane (PEM), which is composed of a thermoplastic elastomer coated with a platinum catalyst. U.S. car-makers expect to have fuel cell-powered cars on the market by 2004. Polymer selection depends on, among other criteria, fuel selection such as Direct Methanol Fuel Cell (DMFC) or Direct Hydrogen Fuel Cell (DHFC). One prototype fuel cell vehicle is the product of the Partnership for a New Generation of Vehicles (PNGV), comprising U.S. automotive companies and the U.S. Department of Energy (DOE). ... 

The third focus of this book centers around fuel cells. Catalysts for fuel cells and for hydrogen production are discussed in one chapter. Catalysts for proton exchange membrane (PEM) fuel cells are described in another chapter. A specific discussion of the aspect of assembly of membrane electrodes in fuel cells is given in another chapter. Catalytic processes in PEM fuel cells are discussed in a separate chapter. The use of nano-size particles of platinum in PEM fuel cells is given in another chapter. Another chapter concerns direct ethanol fuel cells. A separate chapter on alcohol fuel cells generally discusses this area. Another chapter concerns the electrocatalytic oxidation of ethanol which is of key importance in this area of research. 

There is only one example in the literature of polyphosphazene performance in a proton-exchange membrane (PEM) hydrogen fuel ceU. Allcock and Lvov [45] tested a sulfonimide polyphosphazene membrane in a hy-drogen/oxygen fuel cell at room temperature and at 80 °C. The membrane-electrode-assembly (MEA) was fabricated from a 100 xm thick sulfonimide polyphosphazene membrane that was crosslinked with y-radiation (40 MRad). The polymer lEC was 0.99 mmol/g, with an equilibrium water swelling of 42%, and a proton conductivity of 0.058 S/cm. The anode and cathode were prepared from carbon-supported platinum (20% Pt on Vulcan XC-72R) at a Pt loading of 0.33 mg/cm. The electrodes were hot pressed onto the membrane at 65 °C and 400 psi for 30 s. As a reference, a Nafion 117 MEA was also prepared with the same electrode catalyst at a loading of 0.26 mg/cm for the anode and 0.48 mg/cm for the cathode. For Nafion, the electrodes were hot pressed at 125 °C and 1400 psi for 2 min. 

Fuel cells are electrochemical cells where the chemical energy of the fuel was converted into electricity for power generation with high efficiency [1,2]. Industrial purified hydrogen and air are often used in fuel cells to eliminate any pollution or emission, which is known as proton exchange membrane fuel cells (PEMFCs). In a typical PEMFC, a steam of hydrogen is deUvered to the anode side of the membrane electrode assembly (MEA) [3,4], At the anode, it is catalyzed by platinum (Pt) and split into protons and electrons. This oxidation half-cell reaction is represented as follows ... 

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