Key role of fuel cells

Frank Marscheider-Weidemann, Elna Schirrmeister and Annette Roser 

Despite this, the principle of the fuel cell was not able to be developed into a technically mature process for a long time. The main reasons, apart from insufficient knowledge of the electrochemical processes involved, were material problems. Around the turn of the century, the dynamo generator (1866, Siemens), combustion 

The Hydrogen Economy Opportunities and Challenges, ed. Michael Ball and Martin Wietschel. Published by Cambridge University Press. Cambridge University Press 2009. 

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Various types of fuel cells have been developed to generate power according to the applications and load requirements (Chaurasia, 2000). There are several types of electrolyte, which plays a key role in the different types of fuel cells. It must permit only the appropriate ions to pass between the anode and cathode. The main electrolyte types are alkali, molten carbonate, phosphoric acid, proton exchange membrane (PEM), and solid oxide. The first three are liquid electrolytes, the last two are solids. 

These fuel cell results, completed by the different spectroscopic and chromatographic results, allowed us to propose a detailed reaction mechanism of ethanol oxidation, involving parallel and consecutive oxidation reactions, on Pt-based electrodes, where the key role of the adsorption steps was underlined. 

Moreover, due to a net water flow toward the cathode and the production of water in it, oxygen diffusivity will be a function of the current density. At larger current densities larger amounts of water will accumulate within the cathode, thereby, hampering gaseous transport. Modeling approaches that incorporate the important issue of liquid water formation and partial saturation in CCLs have been developed only recently. They reveal a key role of the CCL in regulating the fuel cell water fluxes. 

The water-gas shift (WGS) reaction is one of the oldest catalytic processes employed in the chemical industry. Recently, there is renewed interest in this reaction because of its relevance for producing pure hydrogen for use in fuel cell power systems. Another reason for the increased interest is the key role of the WGS reaction in automotive exhaust processes, since the hydrogen produced is an effective reductant for NOx removal [1]. New technologies require improvements of the WGS catalyst system, and it is desirable to prepare catalysts with high activity at relatively low temperatures and better stability than the commercial Cu/Zn0/Al203 catalyst. The catalyst properties may... 

In Refs. [18,19], the macrohomogeneous theory was extended to include concepts of percolation theory. The resulting structure-based model correlates the performance of the CCL with the volumetric amounts of Pt, C, ionomer, and pores. A detailed review of macroscopic catalyst layer theory can be found in Ref. [17]. A further extension of this theory in Ref. [25] explores the key role of the CCL for the fuel cell water balance. This function is closely linked to the pore size distribution. Major principles of these models will be reproduced here. The details can be found in the literature cited. 

Due to the high H/C ratio (which gives it some envirOTunental advantage) and availability, methane (CH4) may play a key role in the broad introduction of fuel cell technology (Direct Hydrocarbon Solid Oxide Fuel Cells). 

A.R. Jha, author of 10 books on alternative energy and other topics, outlines rechargeable battery requirements for electric vehicles (EVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). He identifies the unique materials for electrolytes, cathodes, and anodes that are most cost-effective with significant improvements in weight, size, efficiency, reliability, safety, and longevity. Since electrode kinetics play a key role in the efficient operation of fuel cells, the book also provides you with a foundation in the basic laws of electrochemical kinetics. 

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