A novel composite cathode La0.6Sr0.4CoO3-delta-Baxr(0.1)Ce(0.7)Y(0.1)Yb(0.1)O(3-delta) for intermediate temperature solid oxide fuel cells

In this study, Baxr(0.1)Ce(0.7)Y(0.1)Yb(0.1)O(3-delta) (BZCYYb) was incorporated into La0.6Sr0.4CoO3-delta (LSC) to form a composite cathode LSC-BZCYYb. The X-ray diffraction (XRD) results demonstrate that BZCYYb has an extremely desirable chemical compatibility with LSC below 1200 degrees C. The thermal expansion coefficient (lEC) measurements indicate that incorporating 30 wt% BZCYYb enables the TEC of the composite cathode to be significantly reduced to 14.7 x 10(-6) K-1 from 20 x 10(-6) K-1 (LSC). The influence of the sintering temperature, composition and thickness on the microstructure as well as the electrochemical properties of the LSC BZCYYb cathode were investigated. A Scanning electron microscope (SEM) testing shows that the LSC BZCYYb cathode sintered at 950 degrees C has an optimum microstructure with good adhesion to the GDC interlayer and higher porosity. Electrochemical measurements reveal that 0.7LSC-0.3BZCYYb sintered at 950 degrees C with a thickness of approximately 20 mu m possesses the minimum activation energy (E-a = 1.32 eV) and polarization resistance (R-p), measuring approximately 0.116 Omega cm(2) at 650 degrees C. This study confirms that the composite 0.7LSC-0.3BZCYYb cathode has the great potential to be a cathode material for intermediate temperature solid oxide fuel cells. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.