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

The layered GdBa0.5Sr0.5Co2O5+delta (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 BaCe0.5Zr0.3Y0.16Zn0.04O3-delta(BCZYZ) as electrolyte. The fabricated single cells of NiO-BCZYZ/BCZYZ (similar to 20 mu m)/GBSC (similar to 20 mu m) were operated from 550 to 700 degrees C with humidified hydrogen (similar to 5% H2O) as fuel. The BCZYZ perovskite electrolyte was completely dense after sintered at 1250 degrees C for 5 h, lower than that without zinc dopant about 150 degrees C. An open circuit voltage of 1.009 V and a maximal power density of 0.35 W cm(-2) were achieved at 700 degrees C. The interfacial polarization resistance was as low as 1.46, 0.45, 0.25 and 0.15 Omega cm(2) at 550, 600,650 and 700 degrees C, respectively. The ratio of polarization resistance to total cell resistance decreased with the increase in the operating temperature, from 62% at 550 degrees C to 23% at 700 degrees C, respectively. The experimental results indicated that GBSC is a promising cathode material for proton-conducting SOFCs. (C) 2009 Elsevier B.V. All rights reserved.