PrBa0.5Sr0.5Co2O5+δ layered peroyskite cathode for intermediate temperature solid oxide fuel cells

Layered perovskite oxides have ordered A-cations localizing oxygen vacancies, and may potentially improve oxygen ion diffusivity and surface exchange coefficient. The A-site-ordered layered perovskite PrBa0.5Sr0.5CO2O5+delta (PBSC) was evaluated as new cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs). The material was characterized using electrochemical impedance spectroscopy in a symmetrical cell system (PBSC/Ce0.9Sm0.1O1.9 (SDC)/PBSC), exhibiting excellent performance in the intermediate temperature range of 500-700 degrees C. An area-specific-resistance (ASR) of 0.23 Omega cm(2) was achieved at 650 degrees C for cathode polarization. The low activation energy (Ea) 124 kJ mol(-1) is comparable to that of La0.8Sr0.2Co3-delta. A laboratory-scaled SDC-based tri-layer cell of Ni-SDC/SDC/PBSC was tested in intermediate temperature conditions of 550 to 700 degrees C. A maximum power density of 1045 mW cm(-2) was achieved at 700 degrees C. The interfacial polarization resistance is as low as 0.285, 0.145, 0.09 and 0.05 Omega cm(2) at 550, 600, 650 and 700 degrees C, respectively. Layered perovskite PBSC shows promising performance as cathode material for IT-SOFCs. Published by Elsevier Ltd.