Madison, WI, United States
Madison, WI, United States

Time filter

Source Type

Lee Y.-L.,1509 University Avenue | Kleis J.,Technical University of Denmark | Rossmeisl J.,Technical University of Denmark | Yang S.-H.,Massachusetts Institute of Technology | Morgan D.,1509 University Avenue
Energy and Environmental Science | Year: 2011

In this work we demonstrate that the experimentally measured area specific resistance and oxygen surface exchange of solid oxide fuel cell cathode perovskites are strongly correlated with the first-principles calculated oxygen p-band center and vacancy formation energy. These quantities are therefore descriptors of catalytic activity that can be used in the first-principles design of new SOFC cathodes. © 2011 The Royal Society of Chemistry.

Curtarolo S.,Duke University | Setyawan W.,Duke University | Hart G.L.W.,Brigham Young University | Jahnatek M.,Duke University | And 10 more authors.
Computational Materials Science | Year: 2012

Recent advances in computational materials science present novel opportunities for structure discovery and optimization, including uncovering of unsuspected compounds and metastable structures, electronic structure, surface, and nano-particle properties. The practical realization of these opportunities requires systematic generation and classification of the relevant computational data by high-throughput methods. In this paper we present Aflow (Automatic Flow), a software framework for high-throughput calculation of crystal structure properties of alloys, intermetallics and inorganic compounds. The Aflow software is available for the scientific community on the website of the materials research consortium, Its geometric and electronic structure analysis and manipulation tools are additionally available for online operation at the same website. The combination of automatic methods and user online interfaces provide a powerful tool for efficient quantum computational materials discovery and characterization. © 2012 Elsevier B.V. All rights reserved.

Lee Y.-L.,1509 University Avenue | Morgan D.,1509 University Avenue
Physical Chemistry Chemical Physics | Year: 2012

Sr doped LaMnO 3 is a perovskite widely used for solid oxide fuel cell (SOFC) cathodes. Therefore, there is significant interest in its defect chemistry. However, due to coupling of defect reactions and inadequate constraints of the defect reaction equilibrium constants obtained from thermogravimetry analysis, large discrepancies (up to 4 eV) exist in the literature for defect energetics for Sr doped LaMnO 3. In this work we demonstrate how ab initio energetics and empirical modelling can be combined to develop a defect model for LaMnO 3. Defect formation enthalpies, including concentration dependence due to defect interactions, are extracted from ab initio energies calculated at various defect concentrations. Defect formation entropies for the defect reactions in LaMnO 3 involving O 2-(solid) ↔ O 2(gas) + 2e - are shown to be accessible through combining the gas phase thermodynamics and simple models for the solid phase vibrational contributions. This simple treatment introduces a useful constraint on fitting defect formation entropies. The predicted defect concentrations from the model show good agreement with experimental oxygen nonstoichiometry vs. P(O 2) for a wide range of temperatures (T = 873-1473 K), suggesting the effectiveness of the ab initio defect energetics in describing the defect chemistry of LaMnO 3. Further incorporating a temperature dependent charge disproportionation energy within 0.0-0.2 eV, the model is capable of describing both defect chemistry and oxygen tracer diffusivity of LaMnO 3. The model suggests an important role for defect interactions which are typically excluded from LaMnO 3 defect models, and sensitivity of the oxygen defect concentration to the charge disproportionation energy in the high P(O 2) region. Similar approaches to those used here can be used to model the defect chemistry for other complex oxides.

Loading 1509 University Avenue collaborators
Loading 1509 University Avenue collaborators