PURPOSE: To provide a fuel cell having an air electrode with a coefficient of thermal expansion approximating that of a solid electrolyte by forming the air electrode from a conductive ceramic whose average ionic radius is limited by a specific perovskite complex compound.
CONSTITUTION: An air electrode is formed of a complex compound represented by formula I (A is at least one kind selected from the elements in the Group 3a of the periodic table other than La; and B is at least one kind selected from a group of Ca, Ba and Sr). A conductive ceramic is used such that (x) and (y) in formula I meet 0.2≤(x)≤0.8 and 0.80≤(y)≤1.10 and that an average ionic radius (r) represented by formula II (RA is ionic radius at the 6 coordination of A element; RB is ionic radius at the 6 coordination of B element) meets 0.988≤(r)≤1.285. A fuel cell, having the air electrode which is thus made to have high electrical conductivity even at high temperatures and has a coefficient of thermal expansion approximating that of a ZrO2 solid electrolyte, can be obtained.
AKIYAMA MASAHIDE
YAMASHITA SHOJI
