Reactive Templated Grain Growth and Thermoelectric Power Factor Enhancement of Textured CuFeO2 Ceramics

Masahiko Tato, Rina Shimonishi, Manabu Hagiwara, Shinobu Fujihara

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The delafossite-type CuFeO2 (CFO) is a promising p-type thermoelectric oxide reported to show a large Seebeck coefficient, but the lack of a texturing method for CFO ceramics limits their thermoelectric performance. Here, we show that textured CFO ceramics with an enhanced thermoelectric power factor can be obtained by a facile process based on the reactive templated grain growth (RTGG) method. Nanorods of α-FeOOH were synthesized by a hydrothermal reaction and used as templates for the RTGG process. Textured CFO ceramics with a high c-axis orientation were obtained by ordinal uniaxial pressing of a mixed powder of the α-FeOOH nanorods and Cu2O particles and subsequent reaction sintering process. The best CFO ceramic with the highest orientation degree (Lotgering factor) of 0.71 was obtained at a sintering temperature of 1020 °C. It was found that textured CFO ceramics were formed through a topotactic conversion process via an intermediate α-Fe2O3 phase. The textured CFO ceramic showed a high in-plane electrical conductivity, leading to an enhanced thermoelectric power factor of 1.4 × 10-4 W m-1 K-2 at 700 K, which is the highest value ever reported for undoped CFO ceramics.

Original languageEnglish
Pages (from-to)1979-1987
Number of pages9
JournalACS Applied Energy Materials
Volume3
Issue number2
DOIs
Publication statusPublished - 2020 Feb 24

Keywords

  • delafossite-type CuFeO
  • FeOOH nanorods
  • oxide thermoelectrics
  • power factor
  • reactive templated grain growth

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Energy Engineering and Power Technology
  • Electrochemistry
  • Materials Chemistry
  • Electrical and Electronic Engineering

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