Polymer electrolyte membrane perfluorinated membranes

S. Tsushima, S. Hirai, K. Kitamura, M. Yamashita, S. Takasel, MRI application for clarifying fuel cell performance with variation of polymer electrolyte membranes Comparison of water content of a hydrocarbon membrane and a perfluorinated membrane. Appl. Magn. Reson. 32, 233-241 (2007)... 

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. 

While Nafion , a perfluorinated polymer developed by DuPont, is the most commonly used proton conductive polymer electrolyte membrane it is an insufficient solution in a number of areas. It has high cationic transport (approximately 9.56 5/cm) [8] but also has high levels of methanol fuel crossover, slow anode kinetics and very high cost [12]. Fuel cell membrane performance can be estimated from the ratio of proton conductivity (a) to methanol permeability (P). The higher the value of a/P, the better the membrane performance would be [13]. Chitosan has been shown to have a much lower methanol permeability than Nafion [14], and as such, a great deal of attention focused on developing chitosan membranes with high levels of ionic conduction and low methanol permeability as delineated in Table 3.1. 

Polymer Electrolyte Fuel Cells, Membrane-Electrode Assemblies > Polymer Electrolyte Fuel Cells, Perfluorinated Membranes... 

Schiraldi DA (2006) Perfluorinated polymer electrolyte membrane durability. Polym Rev 46 315-327... 

Among the various types of fuel cells listed in the preceding, the PEMFC, which uses a sheet of polymer membrane as the solid electrolyte, is the subject of this book. The solid polymer electrolyte membrane is the most important constituent of these fuel cells that allows protons, but not electrons, to pass through. These fuel cells currently use perfluorinated Nafion membranes (Du Pont), which exhibit a number of shortcomings to optimum efficiency. Also, the polymer membranes represent approximately 30% of the material cost of the fuel cell. The membrane in... 

S. M. J. Zaidi and S. U. Rahmtm, Perfluorinated ionomer-boron phosphate composite membranes for polymer electrolyte membranes for fuel cell applications, J. Electrochem. Soc. 152(8), A1590-A1594 (2005). 

To date, many membranes have been developed [3-12] and research has been carried out to develop a high performance membrane to replace perfluorinated polymer electrolyte membranes, such as Nafion membranes. However, no membranes developed to date satisfy aU of the above criteria required for DMFC membranes [2-12]. 

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