Effect of La 3+ substitution on the structural and thermoelectric properties of Ca 3- x La x Co 4 O 9+ δ

J. S. Cha, D. H. Kim, H. Y. Hong, G. H. Kim, K. Park

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

The thermoelectric properties of Ca 3 Co 4 O 9 were optimized by the substitution of La 3+ for Ca 2+ in Ca 3 Co 4 O 9 . The La 3+ substitution significantly enhanced the thermoelectric power factor and reduced the lattice thermal conductivity. The lattice thermal conductivities at 800 °C for x = 0 and 0.3 samples were 1.80 and 1.34 Wm −1 K −1 , respectively. The reduced thermal conductivity was mainly attributed to mass and strain field fluctuations in the crystal lattice. Ca 2.7 La 0.3 Co 4 O 9+ δ showed the largest dimensionless figure-of-merit (0.282 at 800 °C) by combining high power factor and the lowest lattice thermal conductivity. This work demonstrates that the La 3+ substitution is a highly effective approach for improving high-temperature thermoelectric properties.

Original languageEnglish
Pages (from-to)3320-3326
Number of pages7
JournalJournal of the European Ceramic Society
Volume39
Issue number11
DOIs
Publication statusPublished - 2019 Sep
Externally publishedYes

Keywords

  • Electrical conductivity
  • Microstructure
  • Sintering
  • Sol–gel process
  • Thermoelectric properties

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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