A promising cathode for proton-conducting intermediate temperature solid oxide fuel cells: Y0.8Ca0.2BaCo4O7+δ

Y0.8Ca0.2BaCo4O7+δ (YCBC4) was synthesized and investigated as a cathode for proton-conducting intermediate temperature solid oxide fuel cells (IT-SOFCs). Low thermal expansion coefficient (TEC) (~9.9×10−6 K−1) can provide good thermal expansion compatibility with the standard SOFC electrolyte materials. Laboratory-sized quad-layer cells, consisting of NiO–BaZr0.1Ce0.7Y0.2O3−δ (BZCY)/NiO–BZCY/BZCY/YCBC4, were fabricated by a one-step dry-pressing/co-firing process and tested from 550 to 700 °C with humidified hydrogen (~3% H2O) as the fuel and static air as the oxidant, respectively. An excellent power density of 472 mW cm−2 and a low electrode polarization resistance of 0.121 Ω cm2 were obtained at 700 °C. Preliminary results demonstrated that the YCBC4 can be a promising cathode material for proton-conducting IT-SOFCs.