Molten carbonate fuel cells materials

Yuh C, Farooque M (2009) Fuel cells— molten carbonate fuel cells materials and life considerations. Encyclopedia of Electrochemical Power Sources 497-507. doi 10.1016/B978-044452745-5.00270-7... 

Molten Carbonate Fuel Cell. The electrolyte ia the MCFC is usually a combiaation of alkah (Li, Na, K) carbonates retaiaed ia a ceramic matrix of LiA102 particles. The fuel cell operates at 600 to 700°C where the alkah carbonates form a highly conductive molten salt and carbonate ions provide ionic conduction. At the operating temperatures ia MCFCs, Ni-based materials containing chromium (anode) and nickel oxide (cathode) can function as electrode materials, and noble metals are not required. 

K. Hoshino, T. Kohno, Central Research Institute, Mitsubishi Material Co., "Development of Copper Base Anodes for Molten Carbonate Fuel Cells," in The International Fuel Cell Conference Proceedings, NEDO/MITI, Tokyo, Japan, Pgs. I69-I72, 1992. 

Molten Carbonate Fuel Cell The electrolyte in the MCFC is a mixture of lithium/potassium or lithium/sodium carbonates, retained in a ceramic matrix of lithium aluminate. The carbonate salts melt at about 773 K (932°F), allowing the cell to be operated in the 873 to 973 K (1112 to 1292°F) range. Platinum is no longer needed as an electrocatalyst because the reactions are fast at these temperatures. The anode in MCFCs is porous nickel metal with a few percent of chromium or aluminum to improve the mechanical properties. The cathode material is hthium-doped nickel oxide. 

Molten Carbonate Fuel Cell (MCFC) materials problems and life operates best at 550 °C... 

First, we will refer to the direct use of hydrocarbon fuels in an SOFC as direct utilization rather than direct oxidation. Second, we recognize that the broadest definition of direct utilization, exclusive from mechanistic considerations, should include rather conventional use of fuel by internal reforming, with steam being cofed to the fuel cell with the hydrocarbon. Indeed, this nomenclature has been used for many years with molten-carbonate fuel cells. However, because internal reforming is essentially limited to methane and because the addition of steam with the fuel adds significant system complexity, we will focus primarily on systems and materials in which the hydrocarbons are fed to the fuel cell directly without significant amounts of water or oxygen. 

Chapters I to III introduce the reader to the general problems of fuel cells. The nature and role of the electrode material which acts as a solid electrocatalyst for a specific reaction is considered in chapters IV to VI. Mechanisms of the anodic oxidation of different fuels and of the reduction of molecular oxygen are discussed in chapters VII to XII for the low-temperature fuel cells and the strong influence of chemisorhed species or oxide layers on the electrode reaction is outlined. Processes in molten carbonate fuel cells and solid electrolyte fuel cells are covered in chapters XIII and XIV. The important properties of porous electrodes and structures and models used in the mathematical analysis of the operation of these electrodes are discussed in chapters XV and XVI. 

Lim and Winnick [110] examined removal of H2S from a simulated hot coal-gas stream fed to the cathode while elemental sulfur gas was evolved at the anode. This process was performed in a cell that was similar in construction to a molten carbonate fuel cell (Fig. 23). The electrolyte was a mixture of Na2S and Li2S retained in a porous inert matrix material (MgO). The cathodic reaction involved the two-electron reduction of hydrogen sulfide to hydrogen (information on the equilibrium potential for H2S reduction can be obtained from [111] ... 

Wendt, H. Boehme, O. Leidich, F.U. Brenscheidt, T. Materials and production technologies of molten carbonate fuel cells. In Proceedings—Electrochemical Society, Proceedings of the Third International Symposium on Carbonate Fuel Cell Technology, 1993 Vol. 93-3, 485-495. 

Giorgi, L. Moreno, A. Pozio, A. Simonetti, E. Cathode materials for molten carbonate fuel cells. In Carbonate Fuel Cell Technology, Proceedings Electrochemical Society, 1999 Vol. 99-20, 265-286. 

Giorgi, L. Carewska, M. Scaccia, S. Simonetti, E. Giacometti, E. Tulli, R. Development of molten carbonate fuel cell using novel cathode material. Int. J. Hydrogen Energy 1996, 21 (6), 491-496. 

Bohme, O. Leidich, F.U. Salge, H.J. Wendt, H. Development of materials and production technologies for molten carbonate fuel cells. Int. J. Hydrogen Energy 1994, 19 (4), 349-355. 

Arendt, R.H. Alternate matrix materials for molten carbonate fuel cell electrolyte structures. J. Electrochem. Soc. 1982, 129 (5), 979-983. 

Tanimoto, K. Miyazaki, Y. Yanagida, M. Tanase, S. Kojima, T. Okuyama, H. Kodama, T. Alternative matrix materials for molten carbonate fuel cell. Denki Kagaku 1990, 41 (2), 51-55. 

Shoji, C. Matsuo, T. Suzuki, A. Yamamasu, Y. Development of electrolyte plate for molten carbonate fuel cell. In Materials for Electrochemical Energy Storage and Conversion II— Batteries, Capacitors and Fuel Cells, Materials Research Society Symposium Proceedings, 1998 Vol. 496, 211-216. 

There are several types of fuel cells, which are classified primarily by the kind of electrolyte they employ. The materials used for electrolytes have their best conductance only within certain temperature ranges (Hirschenhofer 1994). A few of the most promising types include phosphoric acid fuel cell (PAFC), molten carbonate fuel cell (MCFC), solid oxide fuel cell (SOFC), alkaline fuel cell (AFC), proton exchange membrane fuel cell (PEMFC), and direct methanol fuel cell (DMFC). 

Kim Y-S, Yi C-W, Choi H S and Kim K (2011), Modification of Ni-based cathode material for molten carbonate fuel cells using C03O4 , J Power Sources, 196, 1886-1893. 

Paoletti C, Carewska M, Lo Presti R and Me Phail S (2009), Performance analysis of new cathode materials for molten carbonate fuel cells ,/Power Sonreas, 193,... 

There exist a variety of fuel cells. For practical reasons, fuel cells are classified by the type of electrolyte employed. The following names and abbreviations are frequently used in publications alkaline fuel cells (AFC), molten carbonate fuel cells (MCFC), phosphoric acid fuel cells (PAFC), solid oxide fuel cells (SOFC), and proton exchange membrane fuel cells (PEMFC). Among different types of fuel cells under development today, the PEMFC, also called polymer electrolyte membrane fuel cells (PEFC), is considered as a potential future power source due to its unique characteristics [1-3]. The PEMFC consists of an anode where hydrogen oxidation takes place, a cathode where oxygen reduction occurs, and an electrolyte membrane that permits the transfer of protons from anode to cathode. PEMFC operates at low temperature that allows rapid start-up. Furthermore, with the absence of corrosive cell constituents, the use of the exotic materials required in other fuel cell types is not required [4]. 

Electrochemical applications of a-BN include its use as carrier material for catalysts in fuel cells [297], as a constituent of electrodes in molten salt fuel cells [298, 299], as anticracking particles in the electrolyte for molten carbonate fuel cells [300, 301], and in seals for insulating terminals of Li/FeS batteries from the structural case [302], A BN-coated membrane is used in an electrolysis cell for the manufacture of high-purity rare earth metals from salt melts [381]. A porous boron nitride layer is applied to the upper outer surface of the electrolyte tube in sodium-sulfur batteries [303], and ceramic boron nitride separators are used in liquid fuel cells and batteries [304, 305]. Boron nitride powder may be included in the electrolyte of electrolytic capacitors for high-frequency utilization [306]. 

Since thin layers of materials are a necessary part of most fuel cell construction, tape casting has been used extensively in this field. There are two basic types of fuel cells solid oxide fuel cells (SOFC) and molten carbonate fuel cells (MCFC). 

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