Fuel cells, improving

To shed some light on these issues and to be able to have a better understanding of the water transport when using MPLs, Atiyeh et al. [152] presented an experimental method designed to investigate the net water drag coefficient in order to have a better indication of the amount of water flowing from fhe cathode to the anode. They observed that the performance of fhe fuel cell improved when the anode, the cathode, or both had microporous layers. 

Based on an imderstanding of the mechanism of an electrode, an optimization of the electrode structure and catalyst loading are of great significance for fuel cell improvement and cost reduction. A novel electrode composed of core-shell particles with a less costly catalyst presents a much better performance than conventional ones since a core-shell structure provides a large specific area and better catalyst dispersion. 

Research and development effort has been concentrated on the bipolar plate designs to reduce the cost and increase the performance of the fuel cell. Improvements can occur in the performance of a fuel cell through optimization of the channel dimensions and shape in the flow field of bipolar plates. The contact surface area of the reactant gas on the bipolar plates has an effective contribution on the overall reaction of the gases. The reactant gas pressure has an important role in the overall functioning of the fuel cell. Consideration of fluid flow, heat, and mass transfer phenomenon is impor-fanf while designing the bipolar plate channels. 

Anode Catalysts for Direct Methanol Fuel Cells Improved Performance of Binary 171... 

Hydrogen-storage alloys (18,19) are commercially available from several companies in the United States, Japan, and Europe. A commercial use has been developed in rechargeable nickel—metal hydride batteries which are superior to nickel—cadmium batteries by virtue of improved capacity and elimination of the toxic metal cadmium (see BATTERIES, SECONDARYCELLS-ALKALINe). Other uses are expected to develop in nonpolluting internal combustion engines and fuel cells (qv), heat pumps and refrigerators, and electric utility peak-load shaving. 

Even in a simple hydrogen fuel cell system, capital cost reduction requires improvements in many diverse areas, such as catalyst loadings, air pressuriza-... 

However, there are several issues with widespread methanol usage. Methanol production from natural gas is relatively inefficient ( 67%), and this largely offsets the vehicular improvement in efficiency and carbon dioxide reduction (since gasoline can be made with "85% efficiency from oil). Additionally, the PEM fuel cell demands very pure methanol, which is difficult to deliver using existing oil pipelines and may require a new fuel distribution infrastructure. 

Several of the gas turbine cycle options discussed m this section (intercooling, recuperation, and reheat) are illustrated in Figure 4. These cycle options can be applied singly or in various combinations with other cycles to improve thermal efficiency. Other possible cycle concepts that are discussed include thermochemical recuperation, partial oxidation, use of a humid air turbine, and use of fuel cells. 

Radiation-induced grafting and curing processes have been discussed in a number of reviews.203 28 291 The process is widely used for surface modification. Recent applications are the modification of fuel cell membranes and improving... 

If fuel cells could be used in transportation vehicles, it could have a major impact on worldwide consumption of petroleum. Major improvements that are needed for this to happen include increasing the efficiency of fuel cells, increasing their power density, reducing their manufacturing cost, and developing fuel cell designs capable of rapid start-up. 

Sol-gel techniques have been widely used to prepare ceramic or glass materials with controlled microstructures. Applications of the sol-gel method in fabrication of high-temperature fuel cells are steadily reported. Modification of electrodes, electrolytes or electrolyte/electrode interface of the fuel cell has been also performed to produce components with improved microstructures. Recently, the sol-gel method has expanded into inorganic-organic hybrid membranes for low-temperature fuel cells. This paper presents an overview concerning current applications of sol-gel techniques in fabrication of fuel cell components. 

Sol-gel techniques have been successfidly applied to form fuel cell components with enhanced microstructures for high-temperature fuel cells. The apphcations were recently extended to synthesis of hybrid electrolyte for PEMFC. Although die results look promising, the sol-gel processing needs further development to deposit micro-structured materials in a selective area such as the triple-phase boundary of a fuel cell. That is, in the case of PEMFC, the sol-gel techniques need to be expanded to form membrane-electrode-assembly with improved microstructures in addition to the synthesis of hybrid membranes to get higher fuel cell performance. 

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