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

Proton-blocking La 0.7 Sr 0.3 FeO 3− δ –Ce 0.8 Sm 0.2 O 2− δ (LSF–SDC) and proton-conducting La 0.7 Sr 0.3 FeO 3− δ –BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (LSF–BZCY) composites were evaluated as cathodes for BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (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°C, respectively. The results demonstrate that proton-blocking composite cathode is a more preferable alternative for H-SOFC than proton-conducting composite cathode.