Fuel cell, solid polymer nafion

The most successful solid protonic membrane for fuel cell use is NAFION membrane (saturated with aqueous acid solution) used in kW-size fuel cells in the US Gemini space program up to 150 °C. NAFION is a perfluorinated polymer with sulfonic acid groups. 

K. H. Yoon, Nafion/mordenite hybrid membrane for high-temperature operation of polymer electrolyte membrane fuel cell. Solid State Ionics 160 (2003)... 

Solid electrolyte membrane Solid polymer electrolyte fuel cell (thin polymer membrane (Nafion))... 

Jiang J, Kucernak A. 2004. Investigations of fuel cell reactions at the composite microelectrode solid polymer electrol3de interface. I. Hydrogen oxidation at the nanostructured Pt Nafion membrane interface. J Electroanal Chem 567 123-137. 

Proton exchange membrane fuel cell (PEMFC) working at around 70 °C with a polymer membrane electrolyte, such as Nafion, which is a solid proton conductor (conducting by the H + cation). 

The most important use of /3-sultones is for the preparation of fluorinated polymers such as Nafion 64. These solid acid catalysts containing perfluorinated sulfonic acid groups have been known for many years and the presence of the electron-withdrawing F atoms increases the acid strength of the terminal sulfonic acid groups, which become comparable to that of pure sulfuric acid. Prior to the last decade, Nafion had been in use as a superacid, a fuel cell electrolyte and as a membrane-ion separator <1996CHEC-II(1B)1083>. 

The solid polymer electrolyte (SPE) fuel cell makes use of the high stability and the cation selectivity of Nafion, a Teflon-like material that has been modified by the incorporation of sulfonic groups. The membrane is coaled with a porous catalyst on both sides. Hydrogen is oxidized on one side of the membrane and the formed in the process is transported across the membrane to the other side, where it interacts with (OH) ions formed by the reduction of oxygen, to form water. This water is removed from the cell by capillary action with the use of a... 

The perfluorosulfonic acid (Nafion) membrane found its application in fuel cells long before its introduction to the chlor-alkali industry (26-28). The Nafion membrane is used as the solid polymer electrolyte (separator/electrolyte) in fuel cells. Figure 2 shows the schematic of such an SPE fuel cell. 

Recently, Dahr [1], Stonehart [2] and Watanabe [3] have made an attempt to reduce the humidification constraints in solid polymer electrolyte fuel cells (SPEFCs) by using modified perfluorosulfonic membranes. A recast Nafion film sandwiched between the two electrodes was first proposed by Dahr [1] for the realization of an internally humidified SPEFC. Stonehart [2] suggested the inclusion of small amounts of silica powder into the recast film in order to retain the electrochemically produeed water inside the membrane. Watanabe et al [3] have tried to exploit the H2/O2 crossover through the membrane to produce a chemical recombination to water on small Pt clusters inside the membrane. All of these membranes were operated with H2/O2 at 80°C and allowed the development of systems without assisted humidification or with near ambient humidification. 

To improve the performance of low temperature fuel cell systems, effort has been devoted to improving the kinetics of oxygen reduction on platinum at solid polymer electrolyte interfaces. Polymer electrolyte materials, including polyperfluorosulfonic acid polymers such as Nafion -H, have been Incorporated... 

Solid polymer electrolytes, typically perfluorosulfonic acid (PFSA) membranes, are at the core of Polymer electrolyte membrane fuel cells (PEMFCs). These membranes electrically and mechanically isolate the anode and cathode while, when appropriately humidified, allowing for effective ion migration. Nafion, manufactured by DuPont, is one of the most thoroughly used and studied membranes in the PFSA family. Another family of membranes that holds some promise for use in PEMFCs is the group of sulfonated polyaromatic membranes, typically sulfonated polyetherketones. While research is being performed on other types of membranes, as well as hybrid membranes that might have been better-suited properties, information on these is searce [1-10]. 

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