Layered GdBa0.5Sr0.5Co2O5+δ as a cathode for proton-conducting solid oxide fuel cells with stable BaCe0.5Zr0.3Y0.16Zn0.04O3−δ electrolyte

Abstract The layered GdBa 0.5 Sr 0.5 Co 2 O 5+ δ (GBSC) perovskite oxides are synthesized by modified Pechini method and investigated as a novel cathode material for solid oxide fuel cells (SOFCs) based on a stable perovskite oxide BaCe 0.5 Zr 0.3 Y 0.16 Zn 0.04 O 3− δ (BCZYZ) as electrolyte. The fabricated single cells of NiO–BCZYZ/BCZYZ (∼20 μm)/GBSC (∼20 μm) were operated from 550 to 700 °C with humidified hydrogen (∼5% H 2 O) as fuel. The BCZYZ perovskite electrolyte was completely dense after sintered at 1250 °C for 5 h, lower than that without zinc dopant about 150 °C. An open circuit voltage of 1.009 V and a maximal power density of 0.35 W cm −2 were achieved at 700 °C. The interfacial polarization resistance was as low as 1.46, 0.45, 0.25 and 0.15 Ω cm 2 at 550, 600, 650 and 700 °C, respectively. The ratio of polarization resistance to total cell resistance decreased with the increase in the operating temperature, from 62% at 550 °C to 23% at 700 °C, respectively. The experimental results indicated that GBSC is a promising cathode material for proton-conducting SOFCs.