Improved thermoelectric properties of zone-melted p-type bismuth-telluride-based alloys for power generation

• Published in: Rare metals Vol. 41; no. 5; pp. 1490 - 1495
• Main Authors: Zhai, Ren-Shuang, Zhu, Tie-Jun
• Format: Journal Article
• Language: English
• Published: Beijing Nonferrous Metals Society of China 2022; Springer Nature B.V
• Subjects: Alloying; Biomaterials; Bismuth; Carrier density; Chemistry and Materials Science; Energy; Figure of merit; Intermetallic compounds; Letter; Materials Engineering; Materials Science; Metallic Materials; Nanoscale Science and Technology; Physical Chemistry; Point defects; Tellurides; Tellurium; Thermal conductivity; Thermoelectricity
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-021-01901-2

Zone-melted bismuth-telluride-based alloys (ZM-BT) are extensively applied to manufacture commercial thermoelectric power generators (TEG). Optimizing the average figure of merit ( zT ) during 300–500 K of ZM-BT is favorable for improving the conversion efficiency of common TEGs, and manipulating point defects is the primary approach to reduce their relatively high lattice thermal conductivity ( κ l ) and enhance thermoelectric properties further. Se/Te alloying has been confirmed effective for traditional n-type Bi 2 Te 3 compound, while Se alloying in p-type counterparts is rarely reported. Herein, to further reduce κ l , we introduce Se alloying into p-type Bi 0.3 Sb 1.7 Te 3 to enhance the scattering of high-frequency phonons. Combined with the carrier concentration adjustment via excess Te doping, a high average zT  ~ 0.75 between 300 and 500 K was obtained, 22% higher than that of the pristine ingot. Graphical Abstract