Conductive ceramic materials as a cathode in solid cells - synthesis and parameters

The cathode material in the solid cells must be porous to permit diffusion of oxygen and has to meet the following requirements: high electrical conductivity, thermal and chemical compatibility with electrolyte and high activity for oxygen reduction. The perovskite metallic-ceramic oxides comprise many compounds, which could replace noble metals electrodes in SOFC and gas sensors. Perovskites La0.8Sr0.2(Al0.5Fe0.5)O3, La0.8Sr0.2CoO3, La(Co0.4Ni0.6)O3, Ca0.25La0.75CrO3, Ca0.25La0.75(Cr0.85Al0.15)O3, Sr0.25La0.75CrO3 have been extensively studied as electrode materials active at low temperatures. The powders were examined using thermal analysis, X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy. On the basis of our experiments we present some parameters: electrical resistivity, temperature expansion coefficient, possible interactions (perovskites and YSZ powders), microstructures etc. for these perovskites. (author)