Electronic and structural properties of La0.4Sr0.6Ti1-yCoyO3±d electrode materials for symmetric SOFC studied by hard X-ray Absorption Spectroscopy

NAPOLITANO, FEDERICO; SOLDATI, ANALIA L.; GECK, JOCHEN; LAMAS, DIEGO; SERQUIS, ADRIANA C.

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2013 vol. 38 p. 8965 - 8973

0360-3199

We present combined Synchrotron X-ray Absorption Near Edge Spectroscopy (XANES) andExtended X-ray Absorption Fine Structure (EXAFS) study of La0.4Sr0.6Ti1
yCoyO3d(0 <=y <= 0.5), which are promising electrode materials for symmetric solid oxide fuel cells.The measurements were performed at room temperature at the Ti and the Co K-edges inorder to determine the local structural and electronic changes around the two transitionmetals. We find that Ti remains in a higher formal valence (around 4þ) independent of theCo concentration. In contrast to this, dramatic and systematic changes are observed for theCo as a function of y.We conclude that the stability of the Ti4þ triggers the A-site deficiencyin our samples and predicts that oxygen vacancies are much more easily formed at largeCo content, which in turn will greatly enhance the performance as electrode material.