Oxides solid-oxide fuel cells

Walters KM, Dean AM, Zhu H, Kee RJ (2003) Homogeneous kinetics and equilibriiun predictions of coking propensity in the anode channels of direct oxidation solid-oxide fuel cells using dry natural gas. J Power Sources 123 182-189... 

Solid Oxide Fuel Cell In SOF(7s the electrolyte is a ceramic oxide ion conductor, such as vttriurn-doped zirconium oxide. The conduetKity of this material is 0.1 S/ern at 1273 K (1832°F) it decreases to 0.01 S/ern at 1073 K (1472°F), and by another order of magnitude at 773 K (932°F). Because the resistive losses need to be kept below about 50 rn, the operating temperature of the... 

Solid oxide fuel cells consist of solid electrolytes held between metallic or oxide elecU odes. The most successful fuel cell utilizing an oxide electrolyte to date employs Zr02 containing a few mole per cent of yttrium oxide, which operates in tire temperature range 1100-1300 K. Other electrolytes based... 

Singhal, S.C. (2000) Science and technology of solid-oxide fuel cells, MRS Bull. 25(3), 16. 

Current availability of individual lanthanides (plus Y and La) in a state of high purity and relatively low cost has stimulated research into potential new applications. These are mainly in the field of solid state chemistry and include solid oxide fuel cells, new phosphors and perhaps most significantly high temperature superconductors... 

Solid Oxide Fuel Cell developed by Baur, Preis and Schottk (1951)... 

The tape-casting method makes possible the fabrication of films in the region of several hundred micrometers thick. The mechanical strength allows the use of such a solid electrolyte as the structural element for devices such as the high-temperature solid oxide fuel cell in which zirconia-based solid electrolytes are employed both as electrolyte and as mechanical separator of the electrodes. 

Today, the term solid electrolyte or fast ionic conductor or, sometimes, superionic conductor is used to describe solid materials whose conductivity is wholly due to ionic displacement. Mixed conductors exhibit both ionic and electronic conductivity. Solid electrolytes range from hard, refractory materials, such as 8 mol% Y2C>3-stabilized Zr02(YSZ) or sodium fT-AbCb (NaAluOn), to soft proton-exchange polymeric membranes such as Du Pont s Nafion and include compounds that are stoichiometric (Agl), non-stoichiometric (sodium J3"-A12C>3) or doped (YSZ). The preparation, properties, and some applications of solid electrolytes have been discussed in a number of books2 5 and reviews.6,7 The main commercial application of solid electrolytes is in gas sensors.8,9 Another emerging application is in solid oxide fuel cells.4,5,1, n... 

Figure 3.-/. Operating principle of a solid oxide fuel cell (a) and of a chemical cogenerator (b).41 Reprinted with permission from the American Chemical Society.

Reactions (3.9) to (3.11) proceed rapidly to equilibrium in most anodic solid oxide fuel cell (SOFC) environments and thus H2 (Eq. 3.8) rather than CH4 is oxidized electrochemically resulting in low polarization losses. Upon doubling the stoichiometric coefficients of equation (3.8), summing equations (3.8) to (3.11) and dividing the resulting coefficients by two one obtains ... 

Table 3.1 lists some of the anodic reactions which have been studied so far in small cogenerative solid oxide fuel cells. A more detailed recent review has been written by Stoukides46 One simple and interesting rule which has emerged from these studies is that the selection of the anodic electrocatalyst for a selective electrocatalytic oxidation can be based on the heterogeneous catalytic literature for the corresponding selective catalytic oxidation. Thus the selectivity of Pt and Pt-Rh alloy electrocatalysts for the anodic NH3 oxidation to NO turns out to be comparable (>95%) with the... 

F. Grosz in Proc. 2nd Inti. Symp. on Solid Oxide Fuel Cells, (1991) Athens, Greece ... 

C.G. Vayenas, Catalytic and Electrocatalytic Reactions in Solid Oxide Fuel Cells, Solid State Ionics 28-30, 1521-1539 (1988). 

Yamamoto, Solid oxide fuel cells fundamental aspects and prospects, Electrochim. Acta 45, 2423-2435 (2000). 

S.C. Singhal, Advances in solid oxide fuel cell technology, Solid State Ionics 135, 305-313 (2000). 

I.V. Yentekakis, and C.G. Vayenas, Chemical Cogeneration in Solid Oxide Fuel Cells The Oxidation ofH2Sto S02,/. Electrochem. Soc. 136, 996-1002 (1989). 

The oxidative coupling of CH4 (OCM) in solid oxide fuel cells has attracted considerable attention in recent years because of the strong interest in the production of C2 hydrocarbons from natural gas. Work in this area utilizing solid electrolytes prior to 1999 has been reviewed.53... 

This reaction is of great technological interest in the area of solid oxide fuel cells (SOFC) since it is catalyzed by the Ni surface of the Ni-stabilized Zr02 cermet used as the anode material in power-producing SOFC units.60,61 The ability of SOFC units to reform methane "internally", i.e. in the anode compartment, permits the direct use of methane or natural gas as the fuel, without a separate external reformer, and thus constitutes a significant advantage of SOFC in relation to low temperature fuel cells. 

Solid oxide fuel cell, SOFC anodes, 97 catalysis in, 98,410 cathodes, 96... 

Some studies on materials and methane catalysis for solid oxide fuel cells... 

This presentation reports some studies on the materials and catalysis for solid oxide fuel cell (SOFC) in the author s laboratory and tries to offer some thoughts on related problems. The basic materials of SOFC are cathode, electrolyte, and anode materials, which are composed to form the membrane-electrode assembly, which then forms the unit cell for test. The cathode material is most important in the sense that most polarization is within the cathode layer. The electrolyte membrane should be as thin as possible and also posses as high an oxygen-ion conductivity as possible. The anode material should be able to deal with the carbon deposition problem especially when methane is used as the fuel. 

Performance of an Anode-supported Solid Oxide Fuel Cell in a Mixed-gas Configuration... 

The principle of the A-probe is shown in Fig. 10.2. It is a simple oxygen sensor made in a similar manner to the solid oxide fuel cell discussed in Chapter 8. An oxide that allows oxygen ions to be transported is resistively heated to ensure sufficiently high mobility and a short response time ( 1 s.). 

Tsipis EV, Kharton VV (2008) Electrode materials and reaction mechanisms in solid oxide fuel cells A brief review I. Performance-determining factors. J Solid State Electrochem 12 1039-1060 II. Electrochemical behavior vs. materials science aspects, ibid 1367-1391... 

Molten Carbonate 923 K and Solid Oxide Fuel Cells, 1273 K... 

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