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Title: Synthesis, structure and electrochemical properties of layered La{sub 2}Li{sub 2x}(CO{sub 3}){sub 1−x}O{sub 2+2x}

An oxide ion conductor, La{sub 2}Li{sub 2x}(CO{sub 3}){sub 1−x}O{sub 2+x} (x=0.15), was synthesized using a solid-state reaction, and its structure was subsequently determined by Rietveld refinement analyses of synchrotron X-ray and high-resolution powder neutron diffraction data. These analyses determined that carbonate groups are situated between (La{sub 2}O{sub 2}{sup 2+}){sub n} layers in an ordered arrangement and that both oxygen vacancies and interstitial oxygen ions exist within the carbonate layers, resulting in a composition of La{sub 2}Li{sub 0.3}(CO{sub 3}){sub 0.85}O{sub 2.3}. This material is structurally stable up to 500 °C and exhibits a conductivity of 5.5×10{sup −5} S cm{sup −1} at 450 °C. Oxide vacancies associated with carbonate anions appear to be responsible for the ionic conduction observed in this material. - Graphical abstract: Thermal ellipsoid projection of the carbonate layer viewed from the c-axis, showing oxygen migration paths: (A, blue line) interstitial hopping and (B, green line) co-operative rotation. Display Omitted - Highlights: • Lithium insertion in the structure causes the structural changes in carbonate layer. • These structural changes create oxygen vacancies within the flexible carbonate layers and introduce interstitial oxygen. • These interstitial oxygen atoms and oxygen vacancies are involved in oxide ion diffusion through the carbonate layer.
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [1]
  1. Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan)
  2. (Pakistan)
  3. Department of Material and Life Chemistry, Faculty of Engineering, Kanagawa University, 23-817 3-27-1, Rokkakubashi, Kanagawa, Yokohama 221-8686 (Japan)
Publication Date:
OSTI Identifier:
22274098
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 206; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANIONS; CARBONATES; IONIC CONDUCTIVITY; LANTHANUM OXIDES; NEUTRON DIFFRACTION; OXYGEN; OXYGEN IONS; POWDERS; SOLID ELECTROLYTES; SOLIDS; SYNTHESIS; X RADIATION