Significant promotion of ORR activity for Ca3Co4O9+δ cathode by reaction product of electrode and electrolyte

Ca 3 Co 4 O 9+δ (CCO) cathode has been extensively studied for its excellent thermal expansion matching with commonly used electrolytes. CCO composite cathode with different concentrations of La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3 (LSGM) was prepared to evaluate its performance on LSGM electrolyte in this work. The appropriate amount of LaCoO 3 generated by the in-situ reaction of CCO and LSGM under operating conditions significantly enhances the oxygen exchange ability of CCO cathodes. The composite cathode containing 60 wt. % CCO and 40 wt. % LSGM (C-LGM60) exhibits the best electrochemical performance and the lowest polarization impedance among the C-LGM series cathodes. The area-specific resistance (ASR) of C-LGM60 is 0.06 Ωcm 2 at 750 °C. The maximal power density of the electrolyte-supported cell with C-LGM60 cathode reaches 489 mWcm -2 at 800 °C. After a 10 h stabilizing, there is no observable decline of the cell during the next 40 h of discharge. These results encourage the research of using CCO cathode on LSGM electrolytes and make valuable improvements on the development of SOFC cathode.