Preparation, chemical stability and electrochemical properties of LSCF–CBO composite cathodes

La0.6Sr0.4Co0.2Fe0.8O3–Ce0.7Bi0.3O2 (LSCF–CBO) composite electrode has been prepared by polymer–gel method. SEM results showed that the composite electrode formed good contact with Ce0.9Gd0.1O2−δ (CGO) electrolyte after sintering at 900 °C for 2 h. AC impedance spectroscopy and dc polarization measurements were used to study the composite electrode performances in different atmospheres. The (image)1/2 relationship of Rp (polarization resistance) with oxygen partial pressure has been observed, which indicated that the oxygen adsorption/desorption process was the reaction rate limiting step. The polarization resistance decreased with increasing CBO contents. The optimum value of 35 vol.% CBO in LSCF resulted in 0.16 Ω cm2 area specific resistivity (ASR) at 706 °C in air, which indicated that the LSCF–CBO composite electrode was a promising cathode material in ITSOFC.