Proton exchange membrane manufacturing

The PEM (proton exchange membrane) material is a perfluorosulfonic acid polymer film. Several manufacturers make PEMs in one form or another. We used one made by du Pont called Nation 117. Nation 117 is a transparent polymer film about 175 microns (0.007 inches) thick. Dow Chemical Co., Asahi Chemical Co., and Chloride Engineers Ltd. make something similar. A patent describing how one PEM manufacturer s film is processed is listed in the references section at the end of this article. 

Proton Exchange Membrane Fuel Cells (PEMFCs) are being considered as a potential alternative energy conversion device for mobile power applications. Since the electrolyte of a PEM fuel cell can function at low temperatures (typically at 80 °C), PEMFCs are unique from the other commercially viable types of fuel cells. Moreover, the electrolyte membrane and other cell components can be manufactured very thin, allowing for high power production to be achieved within a small volume of space. Thus, the combination of small size and fast start-up makes PEMFCs an excellent candidate for use in mobile power applications, such as laptop computers, cell phones, and automobiles. 

This survey focuses on recent developments in catalysts for phosphoric acid fuel cells (PAFC), proton-exchange membrane fuel cells (PEMFC), and the direct methanol fuel cell (DMFC). In PAFC, operating at 160-220°C, orthophosphoric acid is used as the electrolyte, the anode catalyst is Pt and the cathode can be a bimetallic system like Pt/Cr/Co. For this purpose, a bimetallic colloidal precursor of the composition Pt50Co30Cr20 (size 3.8 nm) was prepared by the co-reduction of the corresponding metal salts [184-186], From XRD analysis, the bimetallic particles were found alloyed in an ordered fct-structure. The elecbocatalytic performance in a standard half-cell was compared with an industrial standard catalyst (bimetallic crystallites of 5.7 nm size) manufactured by co-precipitation and subsequent annealing to 900°C. The advantage of the bimetallic colloid catalysts lies in its improved durability, which is essential for PAFC applicabons. After 22 h it was found that the potential had decayed by less than 10 mV [187],... 

One of the earliest proton exchange membranes was based on sulfonated polystyrene where divinylbenzene was used as a cross-linking unit for extra stability. Developed by General Electric, this membrane (21) was cheap and easy to manufacture, and it was used for fuel cells in the Gemini space pro-gram.i However, due to the sensitivity of the benzylic hydrogen to radical attack, lifetimes for these membranes under FC operating conditions were quite low. Thus, little work has been carried out on these systems since their inception. 

General. There is no doubt that a comparison (updated in the 1990s) of the potential vs. current density plot for the various fuel cells (see Fig. 13.27) shows that the proton exchange membrane fuel cell with a perfluoropolymer sulfuric acid has superior performance (i.e., higher cell potential and hence efficiency) compared with the other types of fuel cells. Because this cell has been chosen for development by the majority of the automotive manufacturers, special attention is given here to its development. 

Fundamental Research that Underlay Development of this Cell. Three U.S. universities were involved in the work that culminated in manufacture of the proton-exchange membrane by Ballard Power Systems. First, Case-Western Reserve University must be recognized because of the sustained investigations there (Yeager et al., 1961-1983) on the mechanism and catalysis of the reduction of02, the reaction that causes most of the energy losses in the fuel cell. The Electrochemistry of... 

The Proton Exchange Membrane fuel cell manufactured by Ballard Power systems comprises of a stack of some 100-200 carbon plates acting as electrodes and ionizing H2 and O2 at 90°C, which powers the fuel cells. The intended application is in trucks and automobiles. 

The copolymers of polyarylketones, containing imits of naphthalene-sulfonic acid in lateral links, are use in manufacturing of proton-exchange membranes [392]. 

Ballard Power Systems A world leader in developing and manufacturing proton-exchange membrane fuel cells, particularly fuel cell stacks Ballard Power Systems is located in Burnaby, British Columbia, Canada, and was founded by Dr. Geoffrey Ballard in 1979. The company went public in 1993 on the Toronto Exchange, and was listed on NASDAQ (symbol BLDP) in 1995. Company website http //www.ballard.com. 

Puffer RH Jr, Rock SJ (2009) Recent advances in high temperature proton exchange membrane fuel cell manufacturing. J Fuel Cell Sci Technol 6(4) 041013/l-041013/7... 

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