The effects of the substitution of Co by Fe on the crystal chemistry and electrode reaction of the system La1-xBaxCo1-yFeyO3-delta (0.7 <= x <= 0.9), are investigated. The incorporation of Fe stabilizes the cubic perovskite and suppresses the structural transformation of La1-xBaxCoO3-delta from a metastable cubic perovskite to a hexagonal phase below 900 degrees C. The linear expansion decreases with the replacement of Co by Fe. The lowest expansion coefficient value, alpha similar to 20.5 x 10(-6) K-1, was obtained for the samples with Fe content y = 0.6. AC impedance spectroscopy measurements on symmetrical cells reveal the presence of an intermediate (IF) and a low (LF) frequency contributions at T >= 600 degrees C. The LF arc varies with the pO(2), at 700 degrees C, according to a power law with exponent n = -1, indicating oxygen diffusion through the porous of the electrode. The minimum Rp value (0.6 Omega cm(2) at 600 degrees C) was obtained for La0.3Ba0.7Co0.6Fe04O3-delta. At constant temperature, T = 750 degrees C, only the IF contribution varies at a rate of 3 x 10(-4) Omega cm(2) h(-1), while the LF contribution remains constant. Experimental data suggest the growth of the IF arc is caused by the mismatch in the expansion coefficients of the electrode and electrolyte. (C) 2013 Elsevier B.V. All rights reserved.