Polymer electrolyte membranes in fuel cell

S. Tsushima, K. Teranishi, S. Hirai, Magnetic resonance imaging of the water distribution within a polymer electrolyte membrane in fuel cells, Electrochem. Solid-State Lett. 7 (2004) A269-A272. 

POLYMER ELECTROLYTE MEMBRANE IN FUEL CELL MODELING... 

Author s note PEM refers to both proton exchange membrane and polymer electrolyte membrane. In Fuel Cell Technology For Vehicles, PEM refers to polymer electrolyte membrane fuel cells (p. 23) and to proton exchange membrane (PEM) technology (p.l37). 

S. Sundar, W. Jang, C. Lee, Y. Shul and H. Han, Crosslinked sulfonated polyimide networks as polymer electrolyte membranes in fuel cells, J. Polym. Sci. Part B Polym. Phys. 43, 2370-2379 (2005). 

Polymer blend membranes comprising a functional polymer based on sulfonated aryl polymers are used as polymer electrolyte membranes in fuel cells, in particular in low temperature fuel cells (37). The polymers tend to be brittle and the addition of a plasticizer which reduces the brittleness of the polymers is advantageous. 

Alternatively, CNT-polymer composites have been utilized as polymer electrolyte membranes in fuel cell devices (PEMFCs) [111]. Sulfonic acid-functionalized CNTs were blended with Nafion polymer so that the proton transport capability of the polymer matrix could be enhanced appreciably. Ionic conductivity measurements of Nafion and CNT-Nafion membranes revealed almost one order of magnitude higher conductivity for the composite than that for neat matrix. 

Sundar, S., Jang, W., Lee, C., Shul, Y., and Han, H. (2005). Crosslinked sulfonated polyimidenetworks as polymer electrolyte membranes in fuel cells. J. Polym. Sci. Part B Polym. Phys. 43, 2370. Tang, H., Pan, M., Jiang, S., Wan, Z., and Yuan, R. (2005). Self-assembling multi-layer Pd nanoparticles onto Nation membrane to reduce methanol crossover. Colloids Surfaces Physicochem. Eng. Aspects 262(2005), 65. 

Tushima, S., Teranishi, K. and Hirai, S., Magnetic Resonance Imaging of the Water Distribution within a Polymer Electrolyte Membrane in Fuel Cell, Electrochemical and Solid-State Lett., 7, No. 9, A269-A272, 2004. 

The concept of a promoter can also be extended to the case of substances which enhance the performance of an electrocatalyst by accelerating the rate of an electrocatalytic reaction. This can be quite important for the performance, e.g., of low temperature (polymer electrolyte membrane, PEM) fuel cells where poisoning of the anodic Pt electrocatalyst (reaction 1.7) by trace amounts of strongly adsorbed CO poses a serious problem. Such a promoter which when added to the Pt electrocatalyst would accelerate the desired reaction (1.5 or 1.7) could be termed an electrocatalytic promoter, or electropromoter, but this concept will not be dealt with in the present book, where the term promoter will always be used for substances which enhance the performance of a catalyst. 

The DOD has also begun a residential fuel cell demonstration program using polymer electrolyte membrane (PEM) fuel cells ranging in size from 1 to 20 kilowatts. This will include twenty-one PEM fuel cells at nine U.S. military bases. The first units were installed in 2002. 

Fuel cells are the primary technology that will advance hydrogen use (DOE, 1998). Fuel cells are important as they are one component of a system that can efficiently produce electricity for many applications (Jacoby, 1999). It is also widely accepted that fuel cells are environmentally friendly (Hirschenhofer, 1997). Low temperature fuel cells, such as polymer-electrolyte-membrane (PEM) fuel cells, are being considered for many applications including electric power generation in commercial and residential buildings, automobile applications and... 

Smith B, Sridhar S, Khan A, (2005). Solid polymer electrolyte membranes for fuel cell applications-a review. Journal of Membrane Science 259 10-26 Sopian K, Wan Daud W, (2006). Challenges and future developments in proton exchange membrane fuel cells. Renewable Energy 31 719-727 Srinivasan S, (2006). Fuel cells From fundamentals to applications. Springer Science and Business Media LLC, New York... 

The development of conventional room-temperature hydrides based on interme-tallic compounds led to a large number of storage materials exhibiting very favorable sorption enthalpies with values of around 25 kj (mol H2), which can be operated in combination with conventional (80 °C operation temperature) polymer electrolyte membrane (PEM) fuel cells. However, their gravimetric storage capacity is limited to less than 3 wt.% H2. 

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. 

Consider the replicated impedance measurements presented in Table 3.9 for a 5 cm Polymer Electrolyte Membrane (PEM) fuel cell operating at a current of 1 A. The measurements were collected at a frequency of 1 Hz on the same cell using two different sets of instrumentation, the 850C provided by Scribner Associates and the FC350 provided by Gamry Instruments. 

Ballard Generating System s first field trial 250 KW Natural gas Polymer, Electrolyte Membrane (PEM) Fuel Cell Power Generator is sited at the Crane Naval Surface Warfare Center, in Indiana, for a two-year demonstration and testing program. This system would be smaller and simpler if it were... 

M. Watanabe, H. Uchida and M. Emori, Polymer electrolyte membranes incorporated with nanometer-size particles of Pt and/or metal-oxides Experimental analysis of the self-humification and suppression of gas-crossover in fuel cell, J. Phys. Chem., B, 1998, 102, 3129-3137 M. Watanabe, H. Uchida, Y. Seki and M. Emori and P. Stonehart, Self-humidifying polymer electrolyte membranes for fuel cell, J. Electrochem. Soc., 1996, 143, 3847-3852 H. Uchida, Y. Mizuno and M. Watanabe, Suppression of methanol crossover in Pt-dispersed polymer electrolyte membrane for direct methanol fuel cell, Chem. Lett., 2000, 1268-1269 H. Uchida, Y. Ueno, H. Hagihara and M. Watanabe, Self-humidifying electrolyte membranes for fuel cells, preparation of highly dispersed Ti02 particles in Nafion 112, J. Electrochem. Soc., 2003, 150, A57-A62. 

The need to operate at temperatures exceeding 100°C presents difficult new challenges for the polymer electrolytes used in fuel cells. This difficulty stems from the decrease in water content of the polymer electrolytes in the desired temperature range. There is a need for detailed understanding of the impact of poor or zero hydration on membrane and electrode processes in the fuel cell. Water plays a key facilitating role in proton transport thus, lower water content leads to lower conductivity. Lack of water also has important negative consequences for electrode behavior. 

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