Doped Lanthanum Manganite

Cathode Porous Pt Stabilized Zr02 impregnated with praesodymium oxide and covered with SnO doped In203 Doped lanthanum manganite Extrusion, sintering 2 mm thickness 11 X 10 cm/cm°C expansion from room temperature to 1000°C 30-40% porosity... 

Table 1. Oxygen coefficient diffusion in doped lanthanum manganite (x = 0.3) and yttria stabilized zirconia.

Yasuda, I. and Hishinuma, M., Electrical conductivity and chemical diffusion coefficient of strontium-doped lanthanum manganites, Journal of the Electrochemical Society 143, 1996, 1583. 

Fig. 13.22. The monolithic SOFC concept of Argonne National Laboratory. Anode nickel-yttria-stabilized zirconia. Cathode strontium-doped lanthanum manganite. Interconnect doped lanthanum chromite, a, Interconnection b, electron-ion path c, anode d, electrolyte e, cathode. (Reprinted from K. Kordesch,...

Electrodes The anodes of SOFC consist of Ni cermet, a composite of metallic Ni and YSZ, Ni provides the high electrical conductivity and catalytic activity, zirconia provides the mechanical, thermal, and chemical stability. In addition, it confers to the anode the same expansion coefficient of the electrolyte and renders compatible anode and electrolyte. The electrical conductivity of such anodes is predominantly electronic. Figure 14 shows the three-phase boundary at the interface porous anode YSZ and the reactions which take place. The cathode of the SOFC consists of mixed conductive oxides with perovskite crystalline structure. Sr doped lanthanum manganite is mostly used, it is a good /7-type conductor and can contain noble metals. 

I. Yasuda and M. Hishinuma, Electrical conductivity and chemical diffusion coefficient of Sr-doped lanthanum manganites, in T.A. Ramanarayanan, W.L. Worrell and H.L. Tuller (Eds.), Proceedings of the 2nd International Symposium on Ionic and Mixed Conducting Oxide Ceramics. The Electrochemical Society, Pennington, NJ, 1994, pp. 209-221. 

A. Belzner, T.M. Giir and R.A. Huggins, Oxygen chemical diffusion in strontium doped lanthanum manganites. Solid State Ionics, 57 (1992) 327-337. 

The structure of the Rh-doped lanthanum manganite is modified when stabilised in the reduced state the XRD patterns corresponds now to the stoichiometric form LaMn03.oo (orthoihombic, ICDD n° 35-1353), which is slightly different fiom that of (hexagonal, thombohedrally... 

Key words X-ray Absorption Spectra/3d-Transition Metal Oxides/SOFS-Cathodes MaterialsA alence State/Doped Lanthanum Manganite... 

Fig. 2 shows typical examples for the Mn K-edge of mixed-valence calcium doped lanthanum manganite (Lao.eCao MnOs). Quasi-chemical formula of this compound can look as ... 

Figure 2. Mn K-edge of calcium doped lanthanum manganite (Lao Cao MnOs)...

The tubular design is probably the best-known design. It has been developed by Westinghouse (now Siemens Power generation) [8]. The first concept that was pursued by Westinghouse consisted of an air electrode supported fuel cell tube. In earlier days the tubes were made from calcium-stabilized zirconia on which the active cell components were sprayed. Nowadays this porous supported tube (PST) is replaced by a doped lanthanum manganite (LaMn) air electrode tube (AES) that increases the power density by about 35 %. The LaMn tubes are extruded and sintered and serve as the air electrode. The other cell components are deposited on this construction by plasma spraying. 

The cathodes consist of manganites or cobaltites of lanthanum doped with divalent metal ions, for example, Lai (Srj(Mn03 (LSM) or Lax (Srj(Co03 (LSC), where 0.15 cathode materials also have some electronic conductivity that secures a uniform current distribution over the entire electrode. The doped lanthanum cobaltite has a higher ionic conductivity than the doped lanthanum manganite, but is more expensive and leads to problems, in particular on account of a possible chemical interaction with the electrolyte. 

Strontium-doped lanthanum manganite synthesis for solid oxide fuel cells cathode. Journal of New Materials for Electrochemical Systems, Vol. 12, No. 2-3, (1 April 2009), pp. (109-113), ISSN 1480-2422... 

Ahlgren, E. O., andPoulsen, F. W. (1996). Thermoelectric power and electrical conductivity of strontium-doped lanthanum manganite. Solid State Ionics 86-88 1173-1178. 

Endo, A., Ihara, M., Komiyama, H., and Yamada, K. (1996). Cathodic reaction mechanism for dense Sr-doped lanthanum manganite electrodes. Solid State Ionics 86-88 ... 

Berger, D. Matei, C. Papa, F. Macovei, D. Fruth, V. Deloume, J.P. (2007). Pure and Doped Lanthanum Manganites Obtained by Combustion Method. Journal of the European Ceramic Society, Vol. 27, No. 13-15, (March 2007), pp. 4395-4398, ISSN 0955-2219... 

Fig. 2 Schematic of SOFC operation presenting the four-step anodic. H2O formation and electron transfer were shown in the insert. LSM strontium-doped lanthanum manganite (cathode for SOFC), Vq" vacancy of oxygen...

Stochniol G, SyskaMs E, Naoumidis A (1995) Chemical cmnpatibifity between strontium-doped lanthanum manganite and yttiia-stabllized ziiconia. J Am Ctaam Soc 78 929—932... 

For the cathode, a mixture of strontium-doped lanthanum manganite (LSM) proved most suitable, and as the slurry spray process was not scalable to larger modules and production volumes, the screen printing process was chosen for the cathode fabrication [76]. 

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