Open AccessMicrostructure and thermoelectric performance of La‐doped (Ca 0.9 Ag 0.1 ) 3 Co 4 O 9 /nano‐sized Ag composite ceramics
Author(s) -
Shi Zongmo,
Zhang Yi,
Zhang Ruizhi,
Lou Zhihao,
Qin Mengjie,
Zhang Ping,
Xu Jie,
Gao Feng,
Yan Haixue
Publication year - 2020
Publication title -
international journal of ceramic engineering and science
Language(s) - English
Resource type - Journals
ISSN - 2578-3270
DOI - 10.1002/ces2.10031
Subject(s) - thermoelectric effect , seebeck coefficient , materials science , microstructure , dopant , electrical resistivity and conductivity , analytical chemistry (journal) , x ray photoelectron spectroscopy , vacancy defect , doping , thermal conductivity , mineralogy , metallurgy , composite material , crystallography , optoelectronics , chemistry , nuclear magnetic resonance , physics , chromatography , thermodynamics , quantum mechanics
(Ca 0.9‐ x Ag 0.1 La x ) 3 Co 4 O 9 /nano‐sized Ag thermoelectric composite ceramics were fabricated by solid‐state reaction method. The influences of La 3+ dopants on the microstructure, band gaps, and thermoelectric properties were investigated. X‐ray photoelectron spectroscopy fitting results showed that the reduction of oxygen vacancy and the increment of trivalent cobalt concentration could significantly improve thermoelectric performance. With the increasing of La 3+ dopants level, the band gaps of samples enlarged. Electrical resistivity decreased from 21.3 to 17.2 mΩ·cm, while Seebeck coefficient increased from 113.3 to 182.3 μV/K. Furthermore, the peak ZT value of 0.18 was obtained at 1073 K for the x = 0.03 sample, resulting from the lower thermal conductivity of 1.05 W/(m·K). The obtained results suggest that the La 3+ substitution, oxygen vacancy, and Ag inclusions can dramatically improve the thermoelectric performance of Ca 3 Co 4 O 9 composites.