Electrical and Oxygen Transport Properties of Ba0.5Sr0.5Co0.8Fe0.2O3-δ

Mónica Burriel 1,2Christian Niedrig 1,2Stefan Baumann 3Stefan F. Wagner 1,2Ellen Ivers-Tiffée 1,2

1. Universitaet Karlsruhe, Inst. f. Werkstoffe der Elektrotechnik IWE, Adenauerring 20 b, Karlsruhe 76131, Germany
2. Karlsruhe Institute of Technology (KIT), Karlsruhe 76131, Germany
3. Forschungszentrum Jülich, Institute of Energy Research IEF (FZJ-IEF), Leo-Brandt-Strasse, Jülich 52425, Germany

Abstract

In the last years, several mixed ionic-electronic conducting (MIEC) materials, such as Sr(Co,Fe)O3-based perovskites, have attracted increasing interest owing to their excellent ionic and electronic transport properties. In particular, Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) shows a high oxygen permeation flux, thus making it a promising candidate for intermediate temperature solid oxide fuel cell cathodes and dense ceramic oxygen permeation membranes. However, several issues, such as its long-term behaviour (stability) as a function of oxygen partial pressure, temperature or in the presence of other gas components (e.g., CO2), are still subject of investigation.

In the present study, polycrystalline BSCF as well as related perovskite compositions of interest for similar applications (e.g., La0.58Sr0.4Co0.2Fe0.8O3-δ (LSCF), Pr0.58Sr0.4Co0.2Fe0.8O3-δ (PSCF)) were investigated as bulk samples in an oxygen pump setup with respect to the conductivity behaviour as a function of oxygen partial pressure and temperature. Moreover, surface exchange (kδ) and bulk diffusion (Dδ) coefficients have been determined from measurements on thick film and thin film samples by means of further electro­chemical techniques (impedance spectroscopy, conductivity relaxation in the frequency domain) and are compared with values taken from a literature survey.

 

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Presentation: Oral at E-MRS Fall Meeting 2009, Symposium G, by Christian Niedrig
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-05-11 19:29
Revised:   2009-06-07 00:48