THE STRUCTURE AND CONDUCTIVITY OF LAMN1-ZCRZO3 AND (LA,A)(1-Y)MN1-ZCRZO3 (A=SR, CA) AS AIR CATHODES IN SOLID OXIDE FUEL-CELLS

Doped LaMnO3 systems are used as cathodes in solid oxide fuel cells, m ainly due to their high electronic conductivity, thermal matching to t he electrolyte material and good catalytic activity towards oxygen red uction. Lanthanum deficient LaMnO3 has been shown to have a higher ele ctronic conductivity than stoichiometric LaMnO3, however, the material has been found to sinter more readily causing a reduction in the effi ciency of the cathode. This paper discusses the effect of imparting no n-stoichiometry to the LaMnO3 system with the incorporation of a B sit e dopant, Cr. The paper examines the effect on the conductivity and ph ase present with increased Cr content, a nd shows that Cr in LaMn1-zCr zO3, up to z = 0.15, does not produce an unacceptably large decrease i n the electronic conductivity, especially for a Ca doped, A site defic ient system. Thus, a B site doped system is considered as a possible c andidate for solid oxide fuel cell cathode systems.