Fuel cell polymer membrane

Using proton exchange membranes as electrolytes that are quasi-solid may cause a problem with respect to the perfect wetting of the catalyst particles. In spite of this (initial) difficulty of developing solid polymer membrane fuel cells, water-swollen perfluorinated sulfonic acid polymers such as the commercial Nation have been used for fuel cells very early since they offer the following advantages ... 

Figure 5.22. Bode diagram of the measured impedance spectra, PEM fuel cell (hot-pressed, as-received E-TEK electrodes) at 80°C, at different cell voltages (o) OCV (984 mV), ( ) 901 mV, (A) 797 mV [22], (Reprinted from Electrochimica Acta, 43, Wagner N, Schnumberger W, Muller B, Lang M. Electrochemical impedance spectra of solid-oxide fuel cells and polymer membrane fuel cells, 3785-93, 1998, with permission from Elsevier and from the authors.)...

Wagner N, Schnumberger W, Muller B, Lang M (1998) Electrochemical impedance spectra of solid-oxide fuel cells and polymer membrane fuel cells. Electrochim Acta 43 3785-93... 

PEM fuel cells use a solid proton-conducting polymer as the electrolyte at 50-125 °C. The cathode catalysts are based on Pt alone, but because of the required tolerance to CO a combination of Pt and Ru is preferred for the anode [8]. For low-temperature (80 °C) polymer membrane fuel cells (PEMFC) colloidal Pt/Ru catalysts are currently under broad investigation. These have also been proposed for use in the direct methanol fuel cells (DMFC) or in PEMFC, which are fed with CO-contaminated hydrogen produced in on-board methanol reformers. The ultimate dispersion state of the metals is essential for CO-tolerant PEMFC, and truly alloyed Pt/Ru colloid particles of less than 2-nm size seem to fulfill these requirements [4a,b,d,8a,c,66j. Alternatively, bimetallic Pt/Ru PEM catalysts have been developed for the same purpose, where nonalloyed Pt nanoparticles <2nm and Ru particles <1 nm are dispersed on the carbon support [8c]. From the results it can be concluded that a Pt/Ru interface is essential for the CO tolerance of the catalyst regardless of whether the precious metals are alloyed. For the manufacture of DMFC catalysts, in... 

Farrauto RJ (2005) Introduction to solid polymer membrane fuel cells and reforming natural gas for production of hydrogen. Appl Catal B 56 3-7... 

Obviously the increasing importance of solid electrolytes as employed in solid oxide or polymer membrane fuel cells calls for experimental methods adapted specifically to the needs of these experimental setups, which are considerably different from those employing liquid electrolyte solutions. The number of experimental methods beyond classical electrochemical ones adapted specifically to these requirements was fairly low when preparing this chapter. In most cases standard surface analytical or solid state analytical techniques were employed for an introductory overview see [3]. Nevertheless, these electrochemical systems are not taken into... 

Polymer membrane fuel cell Polyphosphoric acid Poly(4-phenoxybenzo)d-l,4-phen)dene)... 

Recently, polyimides have drawn considerable attention for the development of membranes for fuel cells. In polymer membrane fuel cells, nafion is widely used as membrane. However, the nafion membrane cannot withstand high temperature (>80 °C), so research on the development of polyimide based fuel cell membranes has started [169-173]. Polyimides also find applications in the development of gas separation membranes because of their compact ring structure and less free volume, which restricts the passage of gases. 

Mamlouk M, Kumar SM, Gouerec P, Scott K (2011) Electrochemical and fuel cell evaluation of Co based catalyst for oxygen reduction in anion exchange polymer membrane fuel cells. J Power Sources 196 7594—7600... 

Impedance Spectra of Solid-Oxide Fuel Cells and Polymer Membrane Fuel Cells, Electrochim. Acta 43, 3785-3793. 

PILs are potentially very nsefiil as ionic-condncting electrolytes in electrochemical systems and as proton-condncting electrolytes in polymer membrane fuel cells (PBMFCs). While the properties and use of BAN as a hquid electrolyte have been investigated over a number of years, it was only recently that the potential application of PILs as electrolytes in fuel cells was identified. The nse of PILs as electrolytes are described below, and their use in PBMFCs is described in the following section. 

Bxtensive research is continuing to be conducted into ways to improve polymer membrane fuel cells (PBMFCs), as outlined in recent reviews. " One particular problem associated with PBMFCs is that the proton-conducting membranes require the use of aqueous electrolyte solutions to obtain high proton conductivity, which causes their proton conductivity to be affected by changes in temperature and humidity, limits their use to <100 °C, and requires the constant replacement of lost water. A potential benefit of using PILs as electrolytes in PBMFCs is that the solutions can be anhydrous and, hence, can be operated at temperatures in excess of 100 °C. 

Many PILs have good thermal and chemical stability and, hence, are stable above 100 °C. The PILs that have so far been investigated as potential electrolytes for polymer membrane fuel cells generally have lower proton conductivity than the aqueous solutions conventionally used, but recent PILs developed by Angell et al. have comparable conductivities. ... 

In a recent patent application, Angell et al. described a series of alkylammonimn PILs, which are potentially useful as nonaqueous electrolytes in high-temperature polymer membrane fuel cells. The PILs investigated were stable to temperatures between 200 and 250 C, had conductivities comparable to aqueous solutions, and could be enhanced through the addition of a base with a pA a value intermediate between that of the acid and the base. ... 

In this review, the known range of protie ionie liqnids has been disenssed, inelnding their reported physicoehemical properties and the applieations where they have been used. In comparison to the vast amount of hterature for AILs, there have been relatively few papers on PILs, despite the fact that PILs can be nsed for many of the same applications as AILs, snch as in chromatography, in organic synthesis, as amphiphile self-assembly media, in electrochemistry, and as explosives, as well as additional applications where having an available proton is essential snch as many biological uses and as proton-condncting media for polymer membrane fuel cells. 

Sometimes a direct methanol fuel cell (DMFC) is categorized as yet another type of fuel cell however, according to the previous categorization (based on electrolyte), it is essentially a polymer membrane fuel cell that uses methanol instead of hydrogen as a fuel [1]. 

PEM stands for polymer electrolyte membrane or proton exchange membrane. Sometimes, they are also called polymer membrane fuel cells, or just membrane fuel cells. In the early days (1960s) they were known as solid polymer electrolyte (SPE) fuel cells. This technology has drawn the most attention because of its simplicity, viability, quick startup, and the fact that it has been demonstrated in almost a conceivable application [1],... 

Yang Y, Holdcroft S. Synthetic strategies for controlling the morphology of proton conducting polymer membranes. Fuel Cells 2005 5 171-86. 

Wohn M., Bolwin K., Schnumberger W., Fisher M., Neubrand W., and Eigemberger G. (1998) Dynamic modelling and simulation of a polymer membrane fuel cell including mass transport limitations . International Journal of Hydrogen Energy, 23(3), 213-218. 

Farrauto R. (2001) Catalytic generation of hydrogen for the solid polymer membrane fuel cell . Abstracts of Papers of the American Chemical Society, 222 (FUEL Part 1), 89. 

Mamlouk, M., Scott, K., Horshtll, J.A., and Williams, C. (2011) The effect of electrode parameters on the performance of anion exchange polymer membrane fuel cells. International Journal of Hydrogen Energy, 36,7191-7198. 

Xu, C., Cao,Y, Kumar, R., Wu, X., Wang, X., and Scott, K. (2011) A polybenzimid-azole/sulfonated graphite oxide composite membrane for high temperature polymer membrane fuel cells, J. Mater. Chem., 21, 11359-11364. 

M. Mamlouk, K. Scott, Effect of anion functional groups on the conductivity and performance of anion exchange polymer membrane fuel cells, J. Power Sources, 211 (2012) 140-146. 

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