Oxygen Diffusivity of La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ Perovskite Oxide

Abstract:

La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ composite oxide was prepared and characterized. Dilatometer and four-probe DC were exploited to investigate the thermal expansion and electrical conductivity, respectively. The thermal expansion curve was linear, but it became steeper at the high temperature region, as a result of the loss of lattice oxygen and the formation of oxygen vacancies. The conductivity increased with temperature up to about 600oC, and then decreased due to the loss of lattice oxygen. The maximum conductivity was more than 300 S cm^-1. The chemical diffusion coefficient in La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ was estimated by analyzing the conductivity relaxation behavior. The relaxation process of the conductivity change for La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ was traced as a function of time, at a fixed temperature. It was found that the chemical diffusion coefficients measured at temperatures 720-770oC vary from 710-8 to 110-7 cm2 S-1. The activation energy for oxygen diffusion in La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ, derived from the chemical diffusion coefficient is 40.8±3.6 kJ mol-1.

• Periodical: Advanced Materials Research (Volumes 616-618)
• Pages: 633-637
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.616-618.633
• Online since: December 2012
• Authors: Yan Wei Liu, Zhe Lü
• Keywords: Chemical Diffusion Coefficient, Conductivity Relaxation, La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ, Perovskite, Solid Oxide Fuel Cell (SOFC)

References

[1] Stephen J. Skinner, International Journal of Inorganic Materials, 3 (2001) 113-121.

[2] N.T. Hart, N.P. Brandon, M.J. Day, N. Lapena-Rey, J. Powder Sources, 106 (2002) 42-50.

[3] Masatoshi Katsuki, Shaorong Wang, Masayuki Dokiya, Takuya Hashimoto, Solid State Ionics, 156 (2003) 453-461.

[4] Julia. Bahteeva, Ilia A. Leonidov, Mikhail V. Patrakeev, Edward B. Miberg, Victor L. Kozhevnikov, Kenneth R. Poeppelmeier, J. Solid State Electrochem, (2004) 8: 578-584.

DOI: 10.1007/s10008-003-0486-5

[5] L-W. Tai, M.M. Nasrallah, H.U. Anderson, D.M. Sarlin, S.R. Sehlin, Solid State Ionics, 76 (1995) 259-271.

[6] L-W. Tai, M.M. Nasrallah, H.U. Anderson, D.M. Sarlin, S.R. Sehlin, Solid State Ionics, 76 (1995) 275.

[7] W. Preis, E. Bucher, W. Sitte, J. Power Sources, 106 (2002) 116-121.

[8] H. J. M. Bouwmeester, M. W. Fen Otter, B. A. Boukamp, J. State Electrochem, (2004) 8: 599-605.

[9] W. Preis, E. Bucher, W.Sitte, Solid State Ionics, 175 (2004) 393-397.

[10] B. Ma, U. Balachandran, J.-H. Park, C.U. Segre, Solid State Ionics, 83 (1996) 65-71.

[11] Z.P. Shao, W.S. Yang, Y. Cong, H. Dong, J.H. Tong, G.X. Xiong, J. Membr. Sci, 172 (2000) 177-188.

[12] Z.P. Shao, G.X. Xing, Y. Cong, W.S. Yang, J. Membr. Sci, 164 (2000)167-176.

[13] Y. Teraoka, N. Yoshimatsu, N. Yamazoe and T. Seiyama, Chem. Lett, (1984) 893-896.

[14] G.Ch. Kostogloudis, Ch. Ftikos, Solid State Ionics, 126 (1999) 143-151

DOI: 10.1016/s0167-2738(99)00230-1

[15] J.A. Lane, S.J. Benson, D. Waller, J.A. Kilner, Solid State Ionics, 121 (1999) 201-208.

[16] Teruhisa Horita, Katsuhiko Yamaji, Natsuko Sakai, YuepingXiong, Tohru Kato, Harumi Yokokawa, Tatsuya Kawada, J. Power Sources, 106 (2002) 224-230.

DOI: 10.1016/s0378-7753(01)01017-5

[17] B. Ma, J. –H. Park, and U. Balachandran, J. Electrochem. Soc, 144 (1997) 2816-2823.