Characterization of GdBaCo2O5+δ cathode for IT-SOFCs

Abstract: The mixed conductor GdBaCo2O5+δ (GBCO) was studied as a promising cathode candidate for IT-SOFCs. It exhibited good chemical compatibility with Sm0.2Ce0.8O1.9 (samaria-doped ceria, SDC) electrolyte as proved by XRD results. Its conductivity was about 512–290Scm−1 in the temperature range 500–800°C. The thermal expansion coefficient (TEC) was about 20.1×10−6 K−1 between 30°C and 900°C in air, which was similar to other cobaltite perovskite cathodes. The sintering temperature had a strong effect on the electrochemical properties of GBCO. DC polarization and ac impedance spectroscopy results confirmed that 1050°C was the optimum sintering temperature. Polarization resistance values for the GBCO cathode on SDC electrolyte were 0.15Ωcm2 at 750°C and 1.11Ωcm2 at 600°C, respectively. [Copyright &y& Elsevier]