Improvement on the high temperature thermoelectric performance of Ga-doped misfit-layered Ca3Co4-xGaxO9+δ (x = 0, 0.05, 0.1, and 0.2)

N. V. Nong, Chia Jyi Liu, Michitaka Ohtaki

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    Abstract

    Highly densified Ca3Co4-xGaxO9+δ (0 ≤ x ≤ 0.2) misfit-layered thermoelectric oxides are prepared by solid state reaction methods followed by hot-pressing. Thermoelectric properties of the samples are measured from room temperature to 1200 K. The results show that partial Ga substitution leads to a simultaneous increase of the electrical conductivity and thermopower. The Ga-doped samples have lower thermal conductivity than that of the non-doped sample in the high temperature region (>600 K). The x = 0.05 sample shows a higher figure of merit (Z = 3.37 × 10-4 K-1) than that of the non-doped sample (Z = 1.98 × 10-4 K-1) at 1073 K, indicating significant improvement of the thermoelectric performance of Ca3Co4O9+δ by partial Ga substitution for Co.

    Original languageEnglish
    Pages (from-to)53-56
    Number of pages4
    JournalJournal of Alloys and Compounds
    Volume491
    Issue number1-2
    DOIs
    Publication statusPublished - Feb 18 2010

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    All Science Journal Classification (ASJC) codes

    • Mechanics of Materials
    • Mechanical Engineering
    • Metals and Alloys
    • Materials Chemistry

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