Microstructure and ionic conductivity of strontium-substituted lanthanum cobaltites

E. Bucher, W. Sitte*, I. Rom, I. Papst, W. Grogger, F. Hofer

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

La0.4Sr0.6CoO3-δ powders were synthesized by the glycine nitrate process. X-ray powder diffraction and selected area electron diffraction (SAED) in the transmission electron microscope (TEM) were used to determine the basic crystal structure of the perovskite samples. Additionally, energy-filtering transmission electron microscopy (EFTEM) was used to evaluate the homogeneity of the samples at the nanometer level. The ionic conductivity σi of La0.4Sr0.6CoO3-δ was obtained from galvanostatic polarization experiments as a function of oxygen non-stoichiometry for 3-δ values between 2.70 and 2.81 (corresponding to pO2 values between 10-4 and 10-1 bar) at 775 and 825 °C. It could be observed that σi shows a maximum which shifts towards larger values of the oxygen non-stoichiometry with increasing temperature. The maximum value was observed at 3-δ=2.79 and 2.77 for 775 and 825 °C, respectively. This behavior has been reported to be indicative of the formation of vacancy-ordered structures which are expected to lower the mobility of oxygen vacancies. The TEM investigations revealed a superstructure within microdomains which were crystallographically oriented perpendicular to each other and were found to be around 100 nm in size.

Original languageEnglish
Pages (from-to)417-421
Number of pages5
JournalSolid State Ionics
Volume152-153
DOIs
Publication statusPublished - 1 Dec 2002

Keywords

  • EFTEM
  • Ionic conductivity
  • Strontium lanthanum cobaltite
  • TEM

ASJC Scopus subject areas

  • Electrochemistry
  • Physical and Theoretical Chemistry
  • Energy Engineering and Power Technology
  • Materials Chemistry
  • Condensed Matter Physics

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