J. Mater. Sci. Technol. ›› 2025, Vol. 223: 114-122.DOI: 10.1016/j.jmst.2024.11.007

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Innovative rotary swaging method drives high performance of n-type Bi2(Te, Se)3 thermoelectrics

Liya Miaoa,b,1, Xiang Lua,1, Qiang Zhanga,*, Xiaojian Tana,b,*, Lidong Chena,b, Kaikai Panga,b, Ruyuan Lia, Qianqian Suna,b, Min Wanga, Peng Suna,b, Jiehua Wua, Guoqiang Liua,b, Zhenlun Songa,b, Jun Jianga,b,*   

  1. aNingbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China;
    bUniversity of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2024-10-21 Revised:2024-11-21 Accepted:2024-11-23 Published:2025-07-10 Online:2024-11-29
  • Contact: *E-mail addresses: qiangzhang@nimte.ac.cn (Q. Zhang), tanxiaojian@nimte.ac.cn (X. Tan), jjun@nimte.ac.cn (J. Jiang)
  • About author:1 These authors contributed equally to this work.

Abstract: The thermoelectric transport of n-type Bi2Te3 heavily depends on grain alignment, causing performance limitations that severely restrict the demand for low-grade waste heat recovery. Here, the n-type Bi2Te2.7Se0.3 material with a certain textured structure is prepared by an innovative rotary swaging method. It is found that various defects including Te vacancies, dislocations, and grain boundaries significantly strengthen the phonon scattering. With an obviously suppressed thermal conductivity and well-maintained carrier mobility, the obtained rods extending up to several tens of centimeters achieve a peak ZT of 1.2 at 450 K and an average ZT of 1.0 (300-550 K), with Vickers hardness and compressive strength increased to 0.42 GPa and 52.6 MPa, respectively. Moreover, the assembled 17-pair thermoelectric module achieves a competitive conversion efficiency of up to 6.3 % and a high output power of 0.93 W at a temperature difference of 250 K. This study develops an effective strategy for synergistically enhancing the thermoelectric and mechanical properties of n-type Bi2(Te,Se)3.

Key words: Bi2 (Te, Se)3, Rotary swaging, Evolutionary microstructure, Thermoelectric module