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MM: Fachverband Metall- und Materialphysik

MM 28: Transport & Diffusion III

MM 28.4: Vortrag

Dienstag, 12. März 2013, 15:45–16:00, H26

Ab initio study of ionic mobility in anisotropic zirconia — •Julian Hirschfeld and Hans Lustfeld — Forschungszentrum Jülich, IAS-1 and PGI-1, Jülich, Germany

Electrolytes with high ionic mobility at lower temperatures are the prerequisite for the success of Solid Oxide Fuel Cells (SOFC). One candidate is Yttrium Stabilized zirconia (YSZ). In the past the ionic resistance of YSZ electrolytes has mainly been decreased by reducing their thickness. But this decreases the resistance only linearly. However, the migration barriers of the oxygen ions influence their mobility exponentially. Recently it has been shown that those barriers can be reduced by applying negative [1] or strong positive [2] pressure.

Here we proceed as follows: Since the ionic motion needs to be good in transport direction only, we have freedom in investigating anisotropic structures. And we have found a peculiar one which - according to density functional (DFT) computations, combined with the Nudged Elastic Band (NEB) method and molecular dynamics (MD) computations - has the potential to outperform YSZ.

[1] T. J. Pennycook et al., PRL 104, 115901 (2010) [2] J. A. Hirschfeld and H. Lustfeld, PRB 84, 224308 (2011)