International Journal of Hydrogen Energy, Vol.43, No.9, 4458-4470, 2018
Layered perovskite LnBa(0.5)Sr(0.5)Cu(2)O(5+delta) (Ln = Pr and Nd) as cobalt-free cathode materials for solid oxide fuel cells
Cobalt-free layered perovskite LnBaosSr(0.5)Cu(2)O(5+delta) (Ln = Pr and Nd, PBSC and NBSC) powders are prepared using combined citrate and EDTA complexing method. The performance of PBSC and NBSC cathode materials are evaluated for solid oxide fuel cells (SOFCs). Two oxidation states (Cu2+/Cu+) for Cu ions exist in LnBa(0.5)Sr(0.5)Cu(2)O(5+delta) oxides. The main valence of Pr ions in PBSC is 3+. The average thermal expansion coefficients (TECs) of PBSC and NBSC are 14.2 and 14.6 x 10(-6) K-1 between 30 and 950 degrees C, which are similar to the TECs of La0.9Sr0.1Ga0.8Mg0.2O3-delta (LSGM) intermediate-temperature electrolyte. The electrical conductivity of PBSC is slightly higher than that of NBSC. At 800 degrees C, the polarization resistance (R-p) values of the PBSC and NBSC cathodes on the LSGM electrolyte are 0.043 and 0.057 Omega cm(2), respectively. The electrolyte-supported single cells were prepared by using PBSC and NBSC as cathode, LSGM as electrolyte (300 mu m thickness), Ce0.9Sm0.1O1.95 (SDC) as interlayer and Ni/SDC as anode. At 850 degrees C, the maximal power densities are obtained as 681 and 651 mW cm(-2) for PBSC and NBSC cathodes. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.