Influence of the synthesis conditions on the crystal structure and properties of GdBaCo2 xFexO5+d oxides as air-electrodes for intermediate temperature solid oxide fuel cells

Abstract

The influence of the synthesis conditions on the crystal structure and properties of the oxides of the system GdBaCo2-xFexO5+d is reported in this article. The materials are prepared by a ceramic method either in air or in an argon atmosphere. Crystal structure characterization is carried out by a combination of powder X-ray diffraction (PXRD) with advanced methods of high resolution transmission electron microscopy (HRTEM), scanning-transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS). Thermal expansion coefficients of the oxides decrease with increasing substitution of Co by Fe. Impedance spectroscopy analysis of symmetrical cells using these materials as electrodes reveals areaspecific polarization resistance (ASR) values low enough for the use of the oxides as air electrodes in intermediate temperature solid oxide fuel cells (IT-SOFCs).