@@@?e?@@ @@@@@@@@@@?@??f?f?f?f?f?f?f?f?f?f?f?f??@? @@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@???@? @?e@??e@??e@??e@??e@??e@??e@??e@??e@??e@??e@??e@??e??@? @?@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@?@?@?@@@?@??@? @?f?f?f?f?f?f?f?f?f?f?f?f?f@?@?f@? @@? @?@@@@@@@??e @@@ @@@?@h?@?@?@@@@@@@?@@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@?@?@f?@?@?@?@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@?@?@?@@@?@?@??@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@?@?@e?@??@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@??@@@?@??@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@f?@?@?@f?@?@ @@@@@@@@@@ @@??@h?@ @@@ Netsu Sokutei 32 5 226-231 2005 9 30 2005 10 21 Thermophysical Properties of Materials for Solid Oxide Fuel Cells (SOFC) Natsuko Sakai (Received September 30, 2005; Accepted October 21, 2005) The data of heat capacity, thermal conductivity, and thermal expansion behavior for materials in solid oxide fuel cells (SOFCs) are reviewed. Most of the SOFC materials are complex metal oxides and their thermal conductivities are generally low, that causes a large temperature distribution during the operation. Since the SOFC consists of metal oxides and composites, a good thermal expansion matching is the most important point in order to fabricate durable cells and stacks. The electrolytes and interconnects are exposed in a large gradient of oxygen partial pressure at a high temperature, and isothermal expansion is observed for rare earth substituted ceria and alkaline earth substituted lanthanum chromites. Although the isothermal expansion in lanthanum chromites can be alleviated by substituting the transition metals, it can not in rare earth substituted ceria. 60 90 80 160 650 750 1000 Solid Oxide Fuel Cell, SOFC 750 1000 (1) 1 kw 58 % LHV 1) (2) 7 2) (3) LHV 25 25 H 2O Lower Heating Value, LHV 2005 The Japan Society of Calorimetry and Thermal Analysis. 226
SOFC SOFC kw kw SOFC Fig.1 SOFC Table 1 O 2 Ni SOFC SOFC SOFC SOFC SOFC Fig.1 Schematic view of a SOFC single cell with an interconnect. SOFC SOFC % 10 % SOFC c /Jg 1 K 1 Table 1 C p /JK 1 mol 1 La 1 x Ca xcro 3 x 0 and 0.2 3) La 0.8Sr 0.2CoO 3 4) LaMnO 3.032 5) Fig.2 La 1 x Ca x CrO 3 Neumann-Kopp 227
Table 1 Thermal and thermophysical properties of materials used in the SOFC stacks. 1 SUS430 2 228
SOFC Cp / JK 1 mol 1 Thermal Diffusivity α / mm 2 s 1 T / K T / K Fig.2 Temperature dependence of molar heat capacity of Fig.3 Temperature dependence of thermal diffusivity: La 1 xca xcro 3, 3) La 0.8Sr 0.2CoO 3, 4) and LaMnO 3.032. 5) LaMnO 3, 5) La 1 xca xcro 3, 3) and YSZ. 6) SOFC Table 1 α LaMnO 3 5) La 1 x Ca xcro 3 δ 3) YSZ 6,7) α Fig.3 LaMnO 3 La 1 x Ca x CrO 3 δ λ /Wm 1 K 1 C p / JK 1 mol 1 ρ /gm 3 α /m 2 s 1 M / g mol 1 λ Cpρα (1) M LaMnO 3 La 1 x Ca x CrO 3 δ 1273 K 2 WK 1 m 1 YSZ Table 1 0 % LaCrO 3 YSZ LaCrO 3 La 1 x Ca x CrO 3 δ La 1 x Ca xcro 3 δ La 3 Ca 2 l /m) λ /Wm 1 K 1 v m /m 3 mol 1 C p /JK 1 mol 1 u /ms 1 l 3λvm (2) C pu 1000 K La 1 x Ca xcro 3 δ 300 pm 3 SOFC SOFC 1273 K YSZ, 8) ScSZ, 9) and LSGM 10) 10.4 10.7 MK 1 11 12 MK 1 1 %H 2 -H 2O 15 MK 1 Ce 4 Ce 3 Yasuda 11) 229
Ce 0.8Gd 0.2O 1.9 800 1.5 % LaCrO 3 1273 K 8.6 9.4 MK 1 La Ca Sr Cr Mg 12-16) (La, Ca)CrO 3 (La, Sr)CrO 3 B Ti 17) Co Al 16) SOFC SOFC SOFC SOFC SOFC 1) J. Akikusa, T. Yamada, T. Kotani, N. Murakami, T. Akbay, A. Hasegawa, M. Yamada, N. Komada, S. Nakamura, N. Chitose, K. Hirata, S. Seto, T. Miyazawa, M. Shibata, K. Hosoi, F. Nishiwaki, T. Inagaki, J. Kanou, S. Ujiie, T. Matsunami, H. Nakajima, J. Nishi, T. Sasaki, H. Yoshida, K. Hashimoto, M. Kawano, S. Yamasaki, Y. Takita, and T. Ishihara, "Solid Oxide Fuel Cells IX" ed. by S. C. Singhal, The Electrochemical Society PV2005-07 p.102 (2005). 2) S. C. Singhal, "Solid Oxide Fuel Cells V" ed. by S. C. Singhal, H. Tagawa, and U. Stimming, The Electrochemical Society PV97-18, p.37 (1995). 3) N. Sakai and S. Stølen, J. Chem. Thermodyn. 28, 421 (1996). 4) L. Yu Barkhatova, A. N. Klimenko, O. F. Kononchuk, A. N. Petrov, and S. V. Sergeev, Russian J. Phys. Chem. 64, 1670 (1990). 5) H. Kobayashi, H. Satoh, and N. Kamegashira, J. Alloys and Comp. 192, 93 (1993). 6) E. S. Fitzsimmons, Gen. Elec. Co. Aircraft Nuclear Propulsion Dept., DC-61-6-4, 1 (1964). 7) D. P. H. Hasselman, L. F. Johnson, L. D. Bentsen, R. Syed, H. L. Lee, and M. V. Swain, Am. Ceram. Soc. Bull. 66, 799 (1987). 8) T. H. Nielsen and M. H. Leipold, J. Am. Ceram. Soc. 47, 155 (1964). 9) O. Yamamoto, Y. Arati, N. Imanishi, Y. Mizutani, M. Kawai, and Y. Nakamura, Solid State Ionics 79, 137 (1995). 10) I. Yasuda, Y. Arati, T. Takeda, N. Imanishi, Y. Mizutani, M. Kawai, and Y. Nakamura, Solid State Ionics 135, 381 (2000). 11) I. Yasuda and M. Hishinuma, "Ionic and Mixed Conducting Ceramics III", eds. T. A. Ramanarayanan, W. L Worrel, H. L. Tuller, A. C. Khandkar, M. Mogensen, and W. Gopel, The Electrochemical Society Proceedings PV-97-24, p.178 (1997). 12) N. Sakai, T. Kawada, H. Yokokawa, M. Dokiya, and T. Iwata, Solid State Ionics 40/41, 394 (1990). 13) S. Hayashi, K. Fukaya, and H. Saito, J. Mater Sci. Lett. 7, 457 (1988). 14) H. E. Hofer and W. F. Kock, J. Electrochem. Soc. 140, 2889 (1993). 15) R. Koc and H. U. Anderson, J. Mater. Sci. Lett. 11, 1191 (1992). 16) I. Yasuda, T. Ogiwara, and T. Yakabe, "Solid Oxide Fuel Cells VII", ed. by H. Yokokawa, S. C. Singhal, The Electrochemical Society PV2001-16, p.783 (2001). 17) K. Mori, H. Miyamoto, K. Takenobu, and T. Matsudaira, "Proceedings of the Third European Solid Oxide Fuel Cell Forum", ed. by P. Stevens, The European Fuel Cell Forum Oberrohrdorf, Switzerland 2, p.179 (1998). 18), 4 (1993). 19) J. H. Kuo, H. U. Anderson, and D. M. Spalin, J. Solid State Chem. 87, 55 (1990). 20) J. Courtures, J. M. Badie, R. Berjoan, and J. Courtures, High Temp. Sci. 13, 331 (1980). 21),,, 89[2], 54 (1981). 22) A. N. Petrov O. F. Kononchuk, A. V. Andreev, V. 230
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