Characterization of LaNixCoyFe1 − x − yO3 as a cathode material for solid oxide fuel cells

We prepared LaNixCoyFe1 − x − yO3 with 0.2 ≤ x ≤ 0.6 and 0.1 ≤ y ≤ 0.4 (LNCF) powder and investigated its characteristics as a cathode material for solid oxide fuel cells. To investigate the crystal structure of LNCF, we analyzed LNCF powder using X-ray diffraction. The crystal structure of LNCF belongs to a rhombohedral system. High total conductivity above 100 S cm− 1 at 1073 K was obtained for LNCF. When x in this system is 0.6, the total conductivity at 1073 K is more than 500 S cm− 1. This conductivity is greater than that of La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) between 323 and 1323 K. The average coefficient of thermal expansion of LNCF is smaller than that of LSCF. To investigate the chemical stability against Cr2O3, we heated LNCF-Cr2O3, LSCF-Cr2O3 and La0.6Sr0.4CoO3 (LSC)-Cr2O3 powder mixtures at 1073 K for 0–1000 h. We found that LNCF powder was less reactive with Cr2O3 than LSCF and LSC powder.