Fabrication and thermoelectric properties of Ca-Co-O ceramics with negative Seebeck coefficient

Chunlin Gong, Zongmo Shi, Yi Zhang, Yongsheng Chen, Jiaxin Hu, Jianjun Gou, Mengjie Qin, Feng Gao

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Ca-Co-O ceramics is typically p-type thermoelectric materials and possesses positive Seebeck coefficient. In this work, n-type Ca-Co-O ceramics with negative Seebeck coefficients were fabricated by sintering and annealing in a reducing atmosphere. The microstructures and thermoelectric properties of the ceramics were investigated. The results show that the carrier concentration and the carrier mobility dramatically increase after the samples were annealed in the reducing atmosphere. The electrical resistivity increases from 0.0663 mΩ·cm to 0.2974 mΩ·cm, while the negative Seebeck coefficients varies from −24.9 μV/K to −56.3 μV/K as the temperature increases from 323 K to 823 K, and the maximum power factor (PF, 1.536 mW/m·K2) is obtained at 623 K. The samples have n-type thermoelectric properties with large PF values and ZT value (ZT = 0.39, 823 K). The unusual results will pave a new way for studying Ca-Co-O thermoelectric ceramics.

Original languageEnglish
Pages (from-to)1233-1238
Number of pages6
JournalResults in Physics
Volume9
DOIs
StatePublished - Jun 2018

Keywords

  • Annealing
  • Negative Seebeck coefficient
  • Reducing atmosphere
  • Thermoelectric ceramic

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