Proton-conducting membrane

Among the proton-conducting membranes Nation or Nafion-like sulfonated perfluorinated polymers should also be mentioned. These materials are used for polymer electrolyte membrane (PEM) fuel cells, and in addition to being chemically very stable, they exhibit high proton conductivity at temperatures lower than 100°C. It is believed that permeability and thermal stability may be increased if tailor-made lamellar nanoparticles are added to a proton conducting polymer. 

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Ren, X. Springer, T. E. and Gottesfeld, S. (1998). Direct Methanol Fuel Cell Transport Properties of the Polymer Electrolyte Membrane and Cell Performance. Vol. 98-27. Proc. 2nd International Symposium on Proton Conducting Membrane Euel Cells. Pennington, NJ Electrochemical Society. 

Figure 15. Extent of methanol crossover through different ETFE proton-conducting membranes. Comparison with the behavior ofNafion 117 ( ).

Apart from the problems of low electrocatalytic activity of the methanol electrode and poisoning of the electrocatalyst by adsorbed intermediates, an overwhelming problem is the migration of the methanol from the anode to the cathode via the proton-conducting membrane. The perfluoro-sulfonic acid membrane contains about 30% of water by weight, which is essential for achieving the desired conductivity. The proton conduction occurs by a mechanism (proton hopping process) similar to what occurs... 

S. R. Narayanan, A. Kindler, B. Jeffries-Nakamura, W. Chun, H. Frank, M. Smart, S. Surampudi, and G. Halpert, in Proc. of the First International Symposium on Proton Conducting Membrane Fuel Cells, Ed. by S. Gottesfield, G. Halpert, and A. R. Landgrebe, The Electrochemical Society, Pennington, NJ, PV 95-23, 1995, pp. 261-266. 

The PEMFCs require expensive polymer membrane (e.g., Nation ), and operate at a low temperature (e.g., 80°C). Although low temperature reduced the cost of material, the heat generated at low temperatures is more difficult to remove. Alternate proton conducting membranes (e.g., inorganic polymer composites) that will operate at a high temperature (e.g., 200°C) are required. The expensive platinum catalyst used for electrochemical reactions can be poisoned by even trace amounts of carbon monoxide in the hydrogen fuel stream. Hence, a more tolerant catalyst material needs to be developed. 

GDE s may be interesting for synthesis cells as depolarized electrodes (e.g. [48]). A hydrogen-consuming anode will work at a low potential that avoids undesired anodic oxidations (e.g. no chlorine evolution in presence of chlorides). In order to reject an excess of the electrolyte from the GDE structure, a proton-conducting membrane (Nafion ) between the GDE and the electrolyte can be used ( Hydrina , De Nora Spa. [49]). 

A.R. Landgrebe, S. Gottesfeld, First International Symposium on Proton Conducting Membrane Fuel Cells, Chicago, h. Proceedings Vol. 95-23, The Electrochemical Society, Inc., Pennington, N.J., 1995. 

Kreuer, K. D. 2001. On the development of proton conducting membranes for hydrogen and methanol fuel cells. Journal of Membrane Science 185 29-39. 

Zhang, L., Ma, C. and Mukerjee, S. 2004. Oxygen reduction and transport characteristics at a platinum and alternative proton conducting membrane interface. Journal of Electroanalytical Chemistry 568 273-291. 

Hiibner, G. and Roduner, E. 1999. EPR investigation of HO radical initiated degradation reactions of sulfonated aromatics as model compounds for fuel cell proton conducting membranes. Journal of Materials Chemistry 9 409- 18. 

Nolte, R., Ledjeff, K., Bauer, M. and Miilhaupt, R. 1993. Partially sulfoanted PAES—A versatile proton conducting membrane material for modern energy conversion technologies. Journal of Membrane Science 83 211-220. 

Asano, N., Aoki, M., Suzuki, S., Miyatake, K., Uchida, H. and Watanabe, M. 2006. Aliphatic/aromatic polyimide ionomers as a proton conductive membrane for fuel cell applications. Journal of the American Chemical Society 128 1762-1769. 

Jeske, M., Soltmann, C., Ellenberg, C., Wilhelm, M., Koch, D. and Grathwohl, G. 2007. Proton conducting membranes for the high temperature-polymer electrolyte membrane-fuel cell (HT-PEMFC) based on functionalized polysiloxanes. 

Edmondson, C. A., Eontanella, J. J., Chung, S. H., Greenbaum, S. G. and Wnek, G. E. 2001. Complex impedance studies of S-SEBS block polymer proton-conducting membranes. Electrochimica Acta 46 1623-1628. 

Deimede, V. A. and Kallitsis, J. K. 2005. Synthesis of polyjarylene ether) copolymers containing pendant PEO groups and evaluation of their blends as proton conductive membranes. Macromolecules 38 9594—9601. 

Code, P, Hult, A., Jannasch, P, Johansson, M., Karlsson, L. E., Lindbergh, G., Malmstrom, E. and Sandquist, D. 2006. A novel sulfonated dendritic polymer as the acidic component in proton conducting membranes. Solid State Ionics 177 787-794. 

Haute, S. and Stimming, U. 2001. Proton conducting membranes based on electrolyte filled microporous matrices. Journal of Membrane Science 185 95-103. 

Allcock, H. R., Hofmann, M. A., Ambler, C. M., Lvov, S. N., Zhou, X. Y., Chalkova, E. and Weston, J. 2002. Phenyl phosphonic functionalized poly(aryloxyphosphanes) as proton-conducting membranes for direct methanol fuel cells. Journal of Membrane Science 201 47-54. 

Dobrovolskii, Y. A., A. E. Ukshe, A. V. Levchenko, et al. 2007. Materials for bipolar plates for proton-conducting membrane fuel cells. Russian Journal of General Chemistry 4 752-765. 

Fig. 5.22 Proton-conducting membrane based on benzyl sulphonic acid siloxane.

Wnek, G. E. Rider, J. N. Serpico, J. M. Einset, A. G. Proceedings of the First International Symposium on Proton Conducting Membrane Fuel Cells, Electrochemical Society 1995 p 247. 

One of the most important parts of the fuel cell is the electrolyte. For polymer-electrolyte fuel cells this electrolyte is a single-ion-conducting membrane. Specifically, it is a proton-conducting membrane. Although various membranes have been examined experimentally, most models focus on Nafion. Furthermore. it is usually necessary only to modify property values and not governing equations if one desires to model other membranes. The models presented and the discussion below focus on Nafion. 

The purpose of the present review is to summarize the current status of fundamental models for fuel cell engineering and indicate where this burgeoning field is heading. By choice, this review is limited to hydrogen/air polymer electrolyte fuel cells (PEFCs), direct methanol fuel cells (DMFCs), and solid oxide fuel cells (SOFCs). Also, the review does not include microscopic, first-principle modeling of fuel cell materials, such as proton conducting membranes and catalyst surfaces. For good overviews of the latter fields, the reader can turn to Kreuer, Paddison, and Koper, for example. 

Kreuer presented an excellent discussion of materials and transport properties of proton conducting membranes other than Nafion. 

Originality Proton-conducting membranes consisting of aromatic sulfonic acid block... 

Analogs of the step 3 product were prepared by Rozhanskii et al. (1) and used in solid electrolytes and proton-conductive membranes. 

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