Thermoelectric Properties of Alumina-Doped Bi0.4Sb1.6Te3 Nanocomposites Prepared through Mechanical Alloying and Vacuum Hot Pressing

Energies

Chung-Kwei Lin¹  May-Show Chen²  Rong-Tan Huang³  Yu-Chun Cheng³  Pee-Yew Lee³ 

[1] School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan;School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan;Institute of Materials Engineering, National Taiwan Ocean University, Keelung 202, Taiwan;

关键词: γ-Al₂O₃/Bi_0.4Sb_1.6Te₃;    thermoelectric material;    mechanical alloying;    nano/microstructure;    vacuum hot pressing;   

DOI  :  10.3390/en81112323

来源: mdpi

【 摘 要 】

In this study, γ-Al₂O₃ particles were dispersed in p-type Bi_0.4Sb_1.6Te₃ through mechanical alloying to form γ-Al₂O₃/Bi_0.4Sb_1.6Te₃ composite powders. The composite powders were consolidated using vacuum hot pressing to produce nano- and microstructured composites. Thermoelectric (TE) measurements indicated that adding an optimal amount of γ-Al₂O₃ nanoparticles improves the TE performance of the fabricated composites. High TE performances with figure of merit (ZT) values as high as 1.22 and 1.21 were achieved at 373 and 398 K for samples containing 1 and 3 wt % γ-Al₂O₃ nanoparticles, respectively. These ZT values are higher than those of monolithic Bi_0.4Sb_1.6Te₃ samples. The ZT values of the fabricated samples at 298–423 K are 1.0–1.22; these ZT characteristics make γ-Al₂O₃/Bi_0.4Sb_1.6Te₃ composites suitable for power generation applications because no other material with a similarly high ZT value has been reported at this temperature range. The achieved high ZT value may be attributable to the unique nano- and microstructures in which γ-Al₂O₃ nanoparticles are dispersed among the grain boundary or in the matrix grain, as revealed by high-resolution transmission electron microscopy. The dispersed γ-Al₂O₃ nanoparticles thus increase phonon scattering sites and reduce thermal conductivity. The results indicated that the nano- and microstructured γ-Al₂O₃/Bi_0.4Sb_1.6Te₃ alloy can serve as a high-performance material for application in TE devices.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.