Berlin 2018 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MM: Fachverband Metall- und Materialphysik
MM 19: Battery Materials
MM 19.5: Vortrag
Dienstag, 13. März 2018, 11:15–11:30, H 0106
Calculation of Phase Stability and Point Defect Properties in the Perovskite LaFeO3 — •Daniel Mutter1, Daniel F. Urban1, and Christian Elsässer1,2 — 1Fraunhofer IWM, Freiburg, Germany — 2University of Freiburg, FMF, Germany
Solid oxide fuel cell (SOFC) and solid oxide electrolyzer cell (SOEC) devices, which transform chemical into electrical energy and vice versa, have the potential to make a significant contribution to the efforts of overcoming future problems of the energy economy. An optimal functionality of the electrodes in such devices requires a high catalytic activity at their surfaces, i.e. the capability for chemisorption and dissociation of O2 molecules, charge transfer to O2−, and incorporation of O2− ions into vacant anion sites of the crystal structure. Promising materials regarding these requirements are perovskites (ABO3), with La, Ba or Sr ions on the A sites, and transition-metal ions (Mn, Fe, Co) on the B sites. Using density functional theory calculations with a Hubbard-U correction, we aim to shed light on the correlation between stoichiometry, point defect concentrations and experimental synthesis conditions in the perovskite LaFeO3 (LFO). The stability region of LFO in the phase diagram and point defect concentrations were calculated taking into account image charge corrections. Employing defect equilibrium reactions and applying the charge neutrality condition, point defect concentrations were obtained for varying elemental chemical potentials, i.e., synthesis conditions. The sensitivity of the results on the choice of the Hubbard-U parameter will be discussed.