Simultaneous Improvement of Electrical and Thermal Transport Properties of Titanium Oxide Ceramic Thermoelectric Materials

Thermoelectric materials can easily realize energy savings by converting untapped waste heat into electricity. Unfortunately, however, the coupling of the thermoelectric parameters limits the conversion efficiency. Herein, we fabricated titanium oxide ceramic thermoelectric materials using a simple...

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Bibliographic Details
Published in:Journal of electronic materials 2022-07, Vol.51 (7), p.3504-3509
Main Authors: Dong, Zhongping, Li, Anyu, Xiao, Shuyan, An, Shengli
Format: Article
Language:English
Subjects:
Argon
Characterization and Evaluation of Materials
Chemistry and Materials Science
Electrical resistivity
Electronics and Microelectronics
Figure of merit
Heat conductivity
Heat transfer
High temperature
Instrumentation
Lattice vacancies
Materials Science
Optical and Electronic Materials
Original Research Article
Oxygen
Power factor
Solid State Physics
Thermal conductivity
Thermoelectric materials
Titanium
Titanium dioxide
Titanium oxides
Transport properties
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Summary:Thermoelectric materials can easily realize energy savings by converting untapped waste heat into electricity. Unfortunately, however, the coupling of the thermoelectric parameters limits the conversion efficiency. Herein, we fabricated titanium oxide ceramic thermoelectric materials using a simple one-step solid-state reaction between TiO 2 and starch at high temperature, and improved the electrical and thermal transport properties simultaneously by adjusting the amount of starch during preparation. With increasing starch, the electrical conductivity and power factor increased and the thermal conductivity decreased significantly. The samples mixed with 7 wt% starch showed rather low thermal conductivity (less than 2.0 W m −1 K −1 ) and a dimensionless figure of merit ( ZT ) close to 0.14K at 973 K. When the samples were sintered in an argon atmosphere, the starch was carbonized in situ into carbon and provided a reducing atmosphere, leading to the appearance of oxygen vacancies in the lattice of titanium oxide. The oxygen vacancies increased with increasing starch in the mixture during preparation, which resulted not only in a narrower band gap of titanium oxide but also enhanced phonon scattering.
ISSN:0361-5235
1543-186X
DOI:10.1007/s11664-022-09642-3