Correlation between the defect structure, conductivity and chemical stability of La(1-y)Sr(y)Fe(1-x)Al(x)O(3-delta) cathodes for SOFC

The chemical compatibility of a La(1-y)Sr(y)Fe(1-x)Al(x)O(3-delta) cathode and an yttria-stabilised ZrO(2) electrolyte (YSZ) was studied for solid-oxide fuel cell (SOFC) applications. The Al addition to the LaFe(1-x)Al(x)O(3) reduces the reactivity with the YSZ associated with increasing tolerance factor. The Sr addition to the LaFe(1-x)Al(x)O(3) leads to Fe(4+) and anion-vacancy formation. The Sr addition hinders the formation of La(2)Zr(2)O(7), but at y greater than or equal to 0.2 promotes the formation of SrZrO(3) at the La(1-y)Sr(y)Fe(1-x)Al(x)O(3-delta)/YSZ interface. At low p(O(2)) the formation of secondary phases is pronounced what could be related to the formation of anion vacancy. (C) 2001 Elsevier Science Ltd. All rights reserved.