Diffusivity of the Oxide Ion in Perovskite Oxides

Department of Materials, Imperial College, London, London SW7 2AZ, UK e-mail j.kilner imperial.ac.uk 

Ishihara (ed.), Perovskite Oxide for Solid Oxide Fuel Cells, 

Fuel Cells and Hydrogen Energy, DOI 10.1007/978-0-387-77708-5 5, Springer Science-1-Business Media, LLC 2009 

When a gradient is imposed on the eoneentration of oxygen, Co, in a material, an oxygen flux Jg is ereated, whieh is deseribed by Fiek s first law  

Philibert [1] has shown that, in a chemical field, Eq. (5.2) can be simplified into the following equation, where Dchem is the chemical diffusion coefficient  

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Kilner, JA., Berenov, A., and Rossiny, J. (2009) Diffusivity of the oxide ion in perovskite oxides, in Perovskite Oxide for Solid Oxide Euel Cells (ed. T. Ishihara), Springer. 

Kilner, J.A. Berenov, A. Rossiny, J. Diffusivity of the Oxide Ion in Perovskite Oxides, In Perovskite Oxide for Solid Oxide Fuel Cells (Ishihara, T. Ed.), Springer, 2009, 95-116. 

The diffusivity of oxide ions in LSGM was further studied by traeer diffusion measurements [37]. Diffusion of oxide ion in perovskite oxide is explained in detail in Chapter 5. LSGM exhibits large values of diffusion eoeffieient, and the observed fast diffusion in LSGM originates from the higher mobility of oxide ions in the perovskite strueture as compared with the fluorite structure (Table 4.2), presumably due to a large free volume in the lattice. 

Fig. 6.8 Nuclear density distribution in the ab plane atz = 0.2 (0 < jc, y < 2 ) of double perovskite-type PAjmmm Lao.64(Tio.92Nbo.o8 02.99 at (a) 1631 K, (b) 1281 K, and (c) 769 K [11]. Contours are in the range 0.05-0.35 fm A with steps of 0.05 ftnA. The solid line in (a) denotes the curved diffusion path of the oxide ions, and the dotted line denotes the direct path between ideal positions. At low temperature (769 K), oxide ions are localized near the equilibrium position (see (c)) at high temperature (1631 K), the oxide ions are dispersed over a wide area between the regular positions (see (a))...

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