Applications electrolyte membrane

The electrocatalytic oxidation of methanol has been widely investigated for exploitation in the so-called direct methanol fuel cell (DMFC). The most likely type of DMFC to be commercialized in the near future seems to be the polymer electrolyte membrane DMFC using proton exchange membrane, a special form of low-temperature fuel cell based on PEM technology. In this cell, methanol (a liquid fuel available at low cost, easily handled, stored, and transported) is dissolved in an acid electrolyte and burned directly by air to carbon dioxide. The prominence of the DMFCs with respect to safety, simple device fabrication, and low cost has rendered them promising candidates for applications ranging from portable power sources to secondary cells for prospective electric vehicles. Notwithstanding, DMFCs were... 

Mustain WE, Kepler K, Prakash J. 2007. CoPd, oxygen reduction electrocatalysts for polymer electrolyte membrane and direct methanol fuel cells. Electrochim Acta 52 2102-2108. Nagy Z, You H. 2002. Applications of surface X-ray scattering to electrochemistry problems. Electrochim Acta 47 3037-3055. 

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. 

In addition to these smaller applications, fuel cells can be used in portable generators, such as those used to provide electricity for portable equipment. Thousands of portable fuel cell systems have been developed and operated worldwide, ranging from 1 watt to 1.5 kilowatts in power. The two primary technologies for portable applications are polymer electrolyte membrane (PEM) and direct methanol fuel cell (DMFC) designs. 

Direct-methanol fuel cells (DMFCs) have attracted considerable attention for certain mobile and portable applications, because of their high specific energy density, low poison emissions, easy fuel handling, and miniaturization [129,130], However, the methanol permeation through electrolyte membranes (usually called methanol cross-over) in DMFCs still is one of the critical problems hindering the commercialization [131,132], Nafion , a... 

One of the applications for hydrogen is for Polymer Electrolyte Membrane (PEM) fuel cells. As mentioned earlier, one application is a hydrogen fuelled hybrid fuel cell / ultra-capacitor transit bus program where significant energy efficiencies can be demonstrated. Another commercial application is for fuel cell powered forklifts and other such fleet applications that requires mobile electrical power with the additional environmental benefits this system provides. Other commercial applications being developed by Canadian industry is for remote back-up power such as the telecommunications industry and for portable fuel cell systems. 

Polymer electrolyte fuel cells (PEFC) deliver high power density, which offers low weight, cost, and volume. The immobilized electrolyte membrane simplifies sealing in the production process, reduces corrosion, and provides for longer cell and stack life. PEFCs operate at low temperature, allowing for faster startups and immediate response to changes in the demand for power. The PEFC system is seen as the system of choice for vehicular power applications, but is also being developed for smaller scale stationary power. For more detailed technical information, there are excellent overviews of the PEFC (1,2). 

Poltarzewski, E., Stoiti, R, Alderucci, V., Wieczorek, W., and Giordano, N. Nation distribution in gas diffusion electrodes for solid polymer electrolyte membrane fuel cell applications. Journal of the Electrochemical Society 1992 139 761-765. 

Wieser, C. 2004. Novel polymer electrolyte membranes for automotive applications—Requirements and benefits. Fuel Cells 4 245-250. 

Jang, W., Sundar, S., Choi, S., Shul, Y. G. and Han, H. 2006. Acid-base polyim-ide blends for the application as electrolyte membranes for fuel cells. Journal of... 

Miyake, N., Wainright, J. S. and Savinell, R. E 2001. Evaluation of a sol-gel derived Nafion/silica hybrid membrane for proton electrolyte membrane fuel cell applications. I. Proton conductivity and water content. Journal of the Electrochemical Society 148 A898-A904. 

Because of its lower temperature and special polymer electrolyte membrane, the proton exchange membrane fuel cell (PEMFC) is well-suited for transportation, portable, and micro fuel cell applications. But the performance of these fuel cells critically depends on the materials used for the various cell components. Durability, water management, and reducing catalyst poisoning are important factors when selecting PEMFC materials. 

Stephen J. Paddison received a B.Sc.(Hon.) in Chemical Physics and a Ph.D. (1996) in Physical/Theoretical Chemistry from the University of Calgary, Canada. He was, subsequently, a postdoctoral fellow and staff member in the Materials Science Division at Los Alamos National Laboratory, where he conducted both experimental and theoretical investigations of sulfonic acid polymer electrolyte membranes. This work was continued while he was part of Motorola s Computational Materials Group in Los Alamos. He is currently an Assistant Professor in the Chemistry and Materials Science Departments at the University of Alabama in Huntsville, AL. Research interests continue to be in the development and application of first-principles and statistical mechanical methods in understanding the molecular mechanisms of proton transport in fuel-cell materials. 

Polybenzazole block copolymers, (III), prepared by Martin et al. (2) were suitable in solid polymer electrolyte membrane applications as a solid polymer electrolyte doped membranes and in fuel cells derived from them. 

Two major barriers to the commercialization of PEM fuel cells are high cost and poor durability. The US Department of Energy has established the durability target of electrolyte membranes for automotive fuel cells at 5,000 h and for stationary fuel cells at 40,000 h with additional cost constraints and operation requirements. In commercial applications, the integrity of fuel cell membranes must... 

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)... 

The best hope for olefin/paraffin facilitated membrane separations seems to be the solid polymer electrolyte membranes discussed earlier, the results of which are shown in Figures 11.21 and 11.22. If stable membranes with these properties can be produced on an industrial scale, significant applications could develop in treating gases from steam crackers that manufacture ethylene and from polyolefin plants. 

Abstract. The constructive and technological features of silicon electrodes of polymer electrolyte membrane fuel cell (PEMFC) are discussed. Electrodes are made with application of modem technologies of integrated circuits, and technologies of macroporous silicon. Also ways of realization of additional functionalities of electrodes to offered constructive - technological performance are considered. 

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... 

---