Wednesday, November 10, 2010
Hall 1 (Salt Palace Convention Center)
Mixed ionic-electronic conductors (MIECs) based on perovskite and double perovskite structures are promising anode materials for solid oxide fuel cells (SOFCs) due to their potentially high tolerance to carbon poisoning and sulfur impurities in the fuel stream. High oxygen ion mobility of the MIECs is of key importance for the overall performance of the SOFC. In this study, we performed density functional theory (DFT) calculations to systematically investigate the effect of doping on both the number of oxygen vacancies and the oxygen ion mobility in doped SrTiO3 perovskite and Sr2Fe1.5Mo0.5O6 double perovskite structures. Calculations were performed using both a periodic MIECs model with GGA-DFT functional PBE and periodic electrostatic embedded cluster model with hybrid DFT functional PBE0. Hybrid exchange helps producing more reliable electronic structures and oxygen ion diffusion barriers. Overall, we observe that metal doping has a significant effect on oxygen ion transport and seems to be a viable route to improve the performance of SrTiO3 and Sr2Fe1.5Mo0.5O6 materials for SOFC applications.