화학공학소재연구정보센터
Journal of Power Sources, Vol.273, 591-599, 2015
NdBaCo2/3Fe2/3Cu2/3O5+delta double perovskite as a novel cathode material for CeO2- and LaGaO3-based solid oxide fuel cells
Double perovslcites LnBaCo(2)O(5+delta) (Ln = rare earth) are explored as cathode materials for intermediate-temperature solid oxide fuel cell. Barriers to the applicability of double perovskite cathodes include high thermal expansion coefficient (TEC) and poor chemical compatibility with common electrolytes. In this paper, we report the characteristics and applicability of a double perovskite NdBaCo2/3Fe2/3O5+delta (NBCFC) cathode on CeO2- and LaGaO3-based electrolytes. NBCFC is found to crystallize in a tetragonal structure. Partial substitution of Fe and Cu for cobalt in NBCFC demonstrates significantly decreased TEC and good chemical compatibility with both Gd0.1Ce0.9O1.95 (GDC) and La0.9Sr0.1Ga0.8MgO3-delta (LSGM) electrolytes, while maintaining its good electrochemical performance. The oxidation states of transition metal cations are Co3+/Co4+, Fe3+/Fe4+, and Cu+/Cu2+, respectively. The average TEC of NBCFC is 15.7 x 10(-6) K-1 between 30 and 850 degrees C, and the polarization resistance values are 0.056 and 0.023 Omega cm(2) at 800 degrees C with GDC and LSGM electrolytes, respectively. The absence of spin-state transition in copper contributes to the TEC reduction. Addition of appropriate amounts of GDC into NBCFC to form NBCFC-GDC composite cathodes further reduce the TEC and improve cathode performance. These results can be used to improve and develop novel double perovskite cathode materials. (C) 2014 Elsevier B.V. All rights reserved.