Proton-Blocking Composite Cathode for Proton-Conducting Solid Oxide Fuel Cell

Proton-blocking La(0.7)Sr(0.3)FeO(3-delta)-Ce(0.8)Sm(0.2)O(2-delta) (LSF-SDC) and proton-conducting La(0.7)Sr(0.3)FeO(3-delta)-BaZr(0.1)Ce(0.7)Y(0.2)O(3-delta) (LSF-BZCY) composites were evaluated as cathodes for BaZr(0.1)Ce(0.7)Y(0.2)O(3-delta) (BZCY)-based proton-conducting solid oxide fuel cell (H-SOFC) comparatively. The XRD results showed that the chemical compatibility of the components in the two composite cathodes was excellent. LSF-BZCY showed lower area specific polarization resistances than LSF-SDC in symmetrical cells, while LSF-SDC exhibited better performance in single cells. Single cells with proton-blocking LSF-SDC cathode displayed remarkable higher open circuit voltages (OCVs) and lower polarization resistances. Correspondingly, single cells with LSF-SDC cathode exhibited higher power densities than those with LSF-BZCY cathode, outputting maximum power densities of 449, 330, 246, 167, and 101 mW . cm(-2) at 700, 650, 600, 550, and 500 degrees C, respectively. The results demonstrate that proton-blocking composite cathode is a more preferable alternative for H-SOFC than proton-conducting composite cathode. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.076111jes] All rights reserved.