Physicochemical properties of non-stoichiometric oxides Mixed conductors: Part I

A. CANEIRO; L. MOGNI; N. GRUNBAUM; F. PRADO

JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY

SPRINGER

Lugar: Berlin; Año: 2011 vol. 103 p. 597 - 606

1388-6150

This is the first part of a review devoted to present the physicochemical properties of non-stoichiometric oxides that exhibit simultaneously ionic and electronic conductivity. Oxides mixed conductors are candidates to be used in electrochemical applications such as oxygen separation membranes, Solid Oxide Fuel Cells (SOFC) and Solid Oxide Electrolysis Cell (SOEC). In the present article, divide in two parts, we review the thermodynamic and transport properties of mixed conductors systems. In Part I is presented the layered mixed conductors Sr3FeMO6+ä (M = Fe, Co, Ni) belonging to the n = 2 member of the Ruddlesden?Popper series A n+1B n O3n+1, while in Part II we discuss results obtained for the Sr1−x La x Fe0.2Co0.8O3−ä perovskites. These perovskite related intergrowth oxides, Sr3FeMO6+ä, intercalate rock-salt layers in the perovskite structure decreasing the tendency of structural transformation at high temperature. The defect structure of these materials has been determined by thermodynamic measurements of the oxygen chemical potential (ìO2) as a function of oxygen content and temperature. The knowledge of the defect structure has shown to be essential to analyze electrical resistivity measurements and neutron powder diffraction data at high temperature to propose mechanisms for the electronic and ionic transport.