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Title: Characterization of grain-boundary phases in Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} solid electrolytes

Two types of Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} (LLZ) pellets were prepared containing Al and Si impurities, and their grain boundaries characterized using scanning electron microscopy (SEM) with energy-dispersed X-ray (EDX) elemental mapping, transmission electron microscopy (TEM), selected-area electron diffraction (SAED), electron energy-loss spectroscopy (EELS), and high-resolution transmission electron microscopy (HRTEM). In the LLZ pellets containing a small amount of both Al and Si, the total conductivity and density were found to be greater than that of LLZ containing Al alone. Using EDX and TEM, the Al and Si were confirmed to accumulate predominantly at grain-boundary regions. EELS and SAED were used to determine the presence of crystallites of LiAl{sub 5}O{sub 8} and LiAlSiO{sub 4} in the Al-only and Si and Al containing specimens, respectively. HRTEM observations clarified that in the case of LiAlSiO{sub 4}, nano-sized particles exist within an amorphous phase matrix, with a microstructure similar to that in a glass-ceramic. The presence of grain-boundary phases is shown to greatly affect the grain boundary resistance, in the case of the LiAlSiO4 glass-ceramic-type phase resulting in a noticeable improvement of the total conductivity. - Highlights: • Total conductivity of LLZ improved by inclusion of Al and Si impurities • Presencemore » of the impurities at grain boundaries detected using SEM and TEM • Structure of grain-boundary phases identified using SAED, EELS, and HRTEM • Improved conductivity correlated with formation of LiAlSiO{sub 4} in grain-boundary phase.« less
Authors:
 [1] ; ; ; ; ;  [1] ; ;  [2] ;  [3]
  1. Nanostructures Research Laboratory, Japan Fine Ceramics Center, 2-4-1 Mutsuno, Atsuta-ku, Nagoya 456-8587 (Japan)
  2. Department of Materials Science and Chemical Engineering, Faculty of Engineering Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka 432-8561 (Japan)
  3. Office of Society-Academia Collaboration for Innovation, Kyoto University, Nishikyo-ku, Kyoto 615-8520 (Japan)
Publication Date:
OSTI Identifier:
22340362
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 91; Other Information: Copyright (c) 2014 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:
36 MATERIALS SCIENCE; CERAMICS; ELECTRON DIFFRACTION; ELECTRONS; ENERGY-LOSS SPECTROSCOPY; GRAIN BOUNDARIES; IMPURITIES; INCLUSIONS; LITHIUM ION BATTERIES; LITHIUM IONS; NANOSTRUCTURES; PARTICLES; SCANNING ELECTRON MICROSCOPY; SOLID ELECTROLYTES; TRANSMISSION ELECTRON MICROSCOPY; X RADIATION