Polymer electrolyte fuel cell ionomer

A membrane ionomer, in particular a polyelectrolyte with an inert backbone such as Nation . They require a plasticizer (typically water) to achieve good conductivity levels and are associated primarily, in their protonconducting form, with solid polymer-electrolyte fuel cells. 

Bose, A. B., Shaik, R., and Mawdsley, J. Optimization of the performance of polymer electrolyte fuel cell membrane electrode assemblies Roles of curing parameters on the catalyst and ionomer structures and morphology. Journal of Power Sources 2008 182 61-65. 

Wilson, M. S., Valerio, J. A., and Gottesfeld, S. Low platinum loading electrodes for polymer electrolyte fuel cells fabricated using thermoplastic ionomers. Electrochimica Acta 1995 40 355-363. 

Major areas of application are in the field of aqueous electrochemistry. The most important application for perfluorinated ionomers is as a membrane separator in chloralkali cells.86 They are also used in reclamation of heavy metals from plant effluents and in regeneration of the streams in the plating and metals industry.85 The resins containing sulfonic acid groups have been used as powerful acid catalysts.87 Perfluorinated ionomers are widely used in worldwide development efforts in the held of fuel cells mainly for automotive applications as PEFC (polymer electrolyte fuel cells).88-93 The subject of fluorinated ionomers is discussed in much more detail in Reference 85. 

The water distribution within a polymer electrolyte fuel cell (PEFC) has been modeled at various levels of sophistication by several groups. Verbrugge and coworkers [83-85] have carried out extensive modeling of transport properties in immersed perfluorosulfonate ionomers based on dilute-solution theory. Fales et al. [109] reported an isothermal water map based on hydraulic permeability and electro-osmotic drag data. Though the model was relatively simple, some broad conclusions concerning membrane humidification conditions were reached. Fuller and Newman [104] applied concentrated-solution theory and employed limited earlier literature data on transport properties to produce a general description of water transport in fuel cell membranes. The last contribution emphasizes water distribution within the membrane. Boundary values were set rather arbitrarily. 

Jinnouchi, R. Okazaki, K. Molecular dynamics study of transport phenomena in perfluorosulfo-nate ionomer membranes for polymer electrolyte fuel cells. J. Electrochem. Soc. 2003, 150 (1), E66-E73. 

Polymer electrolyte fuel cells (PEFCs) have attracted much interest as one of the most promising nonpolluting power sources capable of producing electrical energy with high thermodynamic efficiencies. The key element of PEFCs is a polymer electrolyte membrane (PEM) that serves as proton conductor and gas separator [1, 2, 3,4], The membrane commonly employed in most PEFC developments is based on Nafion, which represents a family of comb-shaped ionomers with a perfiuorinated polymeric backbone and short pendant (side) chains having sulfonic acid end groups... 

The aforementioned polymeric electrolytes have been effectively used in polymer electrolyte fuel cells operating up to In order to study the single cell performance and apart from the high ionic conductivity of the membrane, several parameters residing the MEA constmction must be taken into account in order to have optimum performance of the cell. Some of these parameters are the amount of the catalyst the ionomer-binder used at the electrodes and its percentage, electrode surface and the preparation method, pressure and the temperature of the MEA assembling and design and constmction parameters of the cell. ... 

In the preceding chapter, recent progress on perfluorinated ionomer membranes is reviewed. There is no doubt that the perfluorinated ionomer membranes will dominate in the area of polymer electrolyte fuel cells (PEFCs) for the years to come however, drawbacks peculiar to perfluorinated materials such as high production... 

Polymer Electrolyte Fuel Cells, Mass Transport, Fig. 4 Modeled catalyst layer cutout with a side length of 100 nm. The shown random structure includes 64 carbon particles with a diameter of 28 nm colored in blue. The ionomer coating has a thickness of 10 nm and is shown in colors from green to red... 

Arico AS, Di Blasi A, Brunaccini G, Sergi F, Dispenza G et al. (2010) High temperature operation of a solid polymer electrolyte fuel cell stack based on a new ionomer membrane . Fuel Cells 10 1013. 

Sadeghi, E., Putz, A., and Eikerling, M. 2013a. Effects of ionomer coverage on agglomerate effectiveness in catalyst layers of polymer electrolyte fuel cells. J. Solid State Electrochem., F1159-F1169. 

Uchida, M., Aoyama, Y., Eda, N., and Ohta, A. 1995a. Investigation of the micro structure in the catalyst layer and effects of both perfluorosulfonate ionomer and PTFE-loaded carbon on the catalyst layer of polymer electrolyte fuel cells. 142(12), 4143 149. 

J. Shim, H. Y. Ha, S. A. Hong and I. H. Oh, Chtuacteristics of the Ntifion ionomer-impregnated composite membrane for polymer electrolyte fuel cells, J. Power Sources 109, 412-417 (2002). 

Polymer electrolyte fuel cells (PEFCs) are unique in that they are the only variety of low-temperature fuel cell to utilize a solid electrolyte. The most common polymer electrolyte used in PEFCs is Nafion , produced by DuPont, a perfluorosulfonic ionomer that is commercially available in films of thicknesses varying from 25 to 175 pm. This material has a fluorocarbon polytetrafluoroethylene (PTFE)-kbone with side chains ending in pendant sulfonic acid moieties. The presence of sulfonic acid promotes water uptake, enabling the membrane to be a good protonic conductor, and thereby facilitating proton transport through the cell. This chapter reviews PEFC development, structure, and properties and presents an overview of PEM technology to date. 

Miyatake, K., Watanabe, M. (2006) Emerging membrane materials for high temperature polymer electrolyte fuel cells Durable hydrocarbon ionomers. J. Mater. Chem. 16, 4465-4467. 

Kim, J.H., Kim, H.J., Lim, T.H., Lee, H.I. (2007) Dependence of the performance of a high-temperature polymer electrolyte fuel cell on phosphoric acid-doped polyhenzimi-dazole ionomer content in cathode catalyst layer. Journal of Power Sources, 170, 275-280. 

Gubler, L. Dockheer, S. M. Koppenol, W. H., Radical (HO-, H- and HOO-) formation and ionomer degradation in polymer electrolyte fuel cells. Journal of the Electrochemical Society 2011, 758(7), B755-B769. 

Numerous efforfs have been made to improve existing fhin-film catalysts in order to prepare a CL with low Pt loading and high Pt utilization without sacrificing electiode performance. In fhin-film CL fabrication, fhe most common method is to prepare catalyst ink by mixing the Pt/C agglomerates with a solubilized polymer electrolyte such as Nation ionomer and then to apply this ink on a porous support or membrane using various methods. In this case, the CL always contains some inactive catalyst sites not available for fuel cell reactions because the electrochemical reaction is located only at the interface between the polymer electrolyte and the Pt catalyst where there is reactant access. 

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