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Layered LaSrGa 3 O 7 ‐Based Oxide‐Ion Conductors: Cooperative Transport Mechanisms and Flexible Structures
Author(s) -
Tealdi Cristina,
Mustarelli Piercarlo,
Islam M. Saiful
Publication year - 2010
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201001137
Subject(s) - materials science , oxide , ion , chemical physics , electrical conductor , ionic conductivity , ionic bonding , thermal conduction , relaxation (psychology) , lattice (music) , nanotechnology , conductivity , chemistry , electrode , physics , composite material , social psychology , psychology , organic chemistry , acoustics , electrolyte , metallurgy
Novel melilite‐type gallium‐oxides are attracting attention as promising new oxide‐ion conductors with potential use in clean energy devices such as solid oxide fuel cells. Here, an atomic‐scale investigation of the LaSrGa 3 O 7 ‐based system using advanced simulation techniques provides valuable insights into the defect chemistry and oxide ion conduction mechanisms, and includes comparison with the available experimental data. The simulation model reproduces the observed complex structure composed of layers of corner‐sharing GaO 4 tetrahedra. A major finding is the first indication that oxide‐ion conduction in La 1.54 Sr 0.46 Ga 3 O 7.27 occurs through an interstitialcy or cooperative‐type mechanism involving the concerted knock‐on motion of interstitial and lattice oxide ions. A key feature for the transport mechanism and high ionic conductivity is the intrinsic flexibility of the structure, which allows considerable local relaxation and changes in Ga coordination.