Bi 2 Te 3 -Based Thermoelectric Modules for Efficient and Reliable Low-Grade Heat Recovery

• Published in: Advanced materials (Weinheim) Vol. 36; no. 26; p. e2400285
• Main Authors: Wu, Gang, Zhang, Qiang, Tan, Xiaojian, Fu, Yuntian, Guo, Zhe, Zhang, Zongwei, Sun, Qianqian, Liu, Yan, Shi, Huilie, Li, Jingsong, Noudem, Jacques G, Wu, Jiehua, Liu, Guo-Qiang, Sun, Peng, Hu, Haoyang, Jiang, Jun
• Format: Journal Article
• Language: English
• Published: Germany 01-06-2024
• Subjects: n‐type bismuth telluride; thermoelectric; CuGaTe2; conversion efficiency
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202400285

Bismuth-telluride-based alloy has long been considered as the most promising candidate for low-grade waste heat power generation. However, optimizing the thermoelectric performance of n-type Bi
Te
is more challenging than that of p-type counterparts due to its greater sensitivity to texture, and thus limits the advancement of thermoelectric modules. Herein, the thermoelectric performance of n-type Bi
Te
is enhanced by incorporating a small amount of CuGaTe
, resulting in a peak ZT of 1.25 and a distinguished average ZT of 1.02 (300-500 K). The decomposed Cu
strengthens interlayer interaction, while Ga
optimizes carrier concentration within an appropriate range. Simultaneously, the emerged numerous defects, such as small-angle grain boundaries, twin boundaries, and dislocations, significantly suppresses the lattice thermal conductivity. Based on the size optimization by finite element modelling, the constructed thermoelectric module yields a high conversion efficiency of 6.9% and output power density of 0.31 W cm
under a temperature gradient of 200 K. Even more crucially, the efficiency and output power little loss after subjecting the module to 40 thermal cycles lasting for 6 days. This study demonstrates the efficient and reliable Bi
Te
-based thermoelectric modules for broad applications in low-grade heat harvest.