Ab initio DFT+U analysis of oxygen transport in LaCoO3: The effect of Co3+ magnetic states

Andrew M. Ritzmann, Michele Pavone, Ana B. Muñoz-García, John A. Keith, Emily A. Carter

Research output: Contribution to journalArticle

58 Scopus citations

Abstract

Although solid oxide fuel cells (SOFCs) provide clean and efficient electricity generation, high operating temperatures (T > 800 °C) limit their widespread use. Lowering operating temperatures (600 °C < T < 800 °C) requires developing next-generation mixed ion-electron conducting (MIEC) cathodes that permit facile oxygen transport. One promising MIEC material, La1-xSrxCo1-yFeyO 3 (LSCF), can operate at intermediate temperatures, has a longer cell lifetime, and permits less expensive interconnect materials. However, the road to optimization of LSCF compositions for SOFC applications would benefit from fundamental, atomic-scale insight into how local chemical changes affect its oxygen ion conductivity. We provide this insight using ab initio density functional theory plus U (DFT+U) calculations to analyze the factors governing oxygen transport in the LSCF parent material LaCoO3. We show that oxygen diffusion in LaCoO3 depends strongly on the spin state of the Co3+ ions: in particular, low spin Co3+ promotes higher oxygen vacancy concentrations than other spin states. We also predict that different spin states of Co3+ significantly affect the oxygen ion migration barrier. Through electronic structure analysis, we uncover the fundamental details which govern oxygen diffusivity in LaCoO3. This journal is

Original languageEnglish (US)
Pages (from-to)8060-8074
Number of pages15
JournalJournal of Materials Chemistry A
Volume2
Issue number21
DOIs
StatePublished - Jun 7 2014

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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