Thermochemical compatibility between selected (La,Sr)(Co,Fe,Ni)O3 cathodes and rare earth doped ceria electrolytes

In this paper the results of thermal expansion coefficient measurements of different singly and doubly doped ceria electrolytes, together with results for selected cathode materials from (La,Sr)(Co,Fe,Ni)O3 system are given. A high temperature chemical stability of the cathode–electrolyte interface was measured on 1:1 wt. mixtures of previously characterized ceria and perovskite powders. The samples were heated at 800, 1000 or at 1200 °C in air for 6 or 100 h. Chemical reactivity investigations were conducted using XRD with Rietveld analysis. For all heated samples the crystal structure of both components were preserved. However, their lattice parameters evolved to a different extent, suggesting the existence of cation exchange. A formation of the solid state solution between Ce1−xRExO2−x/2 and La(Co,Fe,Ni)O3−δ was found, with mobile La cation. On the basis of the obtained results a qualitative mechanism of the observed reaction was proposed.