Cr deposition and poisoning on SrCo0.9Ta0.1O3-δ cathode of solid oxide fuel cells

Perovskite type SrCo0.9Ta0.1O3-δ (SCT10) is a promising cathode for solid oxide fuel cell (SOFC), but its stability towards Cr impurities is not yet exploited. Herein, the Cr deposition on the electrochemical performance of SCT10 cathodes is evaluated at 700 °C with a cathodic constant current density of 200 mA cm−2. Both polarization and impedance results reveal that Cr impurities lead to serious performance degradation, especially in wet condition. Significant morphology damages occur after Cr exposure and the formation of SrCrO4 and Co3O4 secondary phases on the cathode surface are determined, which greatly deteriorates the oxygen reduction kinetics and thereby the cathode activity. Our study highlights that surface Sr segregation plays a vital role for Cr deposition and special attention should be paid for the practical applications in SOFC.