Layered perovskite LaBaCuMO5+x (M = Fe, Co) cathodes for intermediate-temperature protonic ceramic membrane fuel cells

Layered perovskite LaBaCuFeO5+x (LBCF) and LaBaCuCoO5+x (LBCC) oxides are synthesized by a modified Pechini method and examined as potential cathode materials for intermediate-temperature protonic ceramic membrane fuel cells (IT-PCMFCs). Thin proton-conducting BaZr0.1Ce0.7Y0.2O3-delta (BZCY) electrolyte and NiO-BaZr0.1Ce0.7Y0.2O3-delta (NiO-BZCY) anode functional layer are prepared over porous anode substrates composed of NiO-BaZr0.1Ce0.7Y0.2O3-delta by a one-step dry-pressing/co-firing process. Laboratory-sized quad-layer cells of NiO-BYCZ/NiO-BYCZ/BYCZ/LBCF (LBCC) are operated from 550 to 700 degrees C with humidified hydrogen (similar to 3% H2O) as fuel and the static air as oxidant. The single cell with LBCF cathode shows peak power densities of only 327 mW cm(-2) at 700 degrees C and 105 mW cm(-2) for 550 degrees C, while the single cell with LBCC cathode shows peak power densities of 432 and 171 mW cm(-2) at 700 and 550 degrees C, respectively. The dramatic improvement of cell performance is attributed to higher cobaltites catalytic activity than that of ferrites for IT-PCMFCs, which is in good agreement with the results of impedance measurement. (C) 2009 Elsevier B.V. All rights reserved.