Bulk Bi-Sb polycrystals underpinned by high electron/phonon mean free path ratio enabling thermoelectric cooling under 77 K
Bi-Sb alloy, as a promising thermoelectric material at cryogenic temperatures, has seen stagnant progress due to challenges in understanding the transport behaviors of energy carriers, and difficulties in synthesizing high-homogeneity, large-grain samples. In this study, an inherent electron-phonon decoupling in Bi-Sb is revealed using the first-principles calculations based on the virtual crystal approximation. The mean free path of the dominant electrons (λ<sub>ele</sub> ~ 10<sup>3</sup> nm) is found of two orders of magnitude larger than that of phonons (λ<sub>ph</sub> ~ 10<sup>1 </sup>nm), suggesting that a grain size greater than 10 μm would be favorable for thermoelectric transport. Bulk Bi-Sb polycrystals with highly elemental homogeneity and large grain size (~80 μm) are successfully synthesized through an ultra-fast quenching method combined with annealing, delivering superior thermoelectric performance. A prototype module based on the Bi<sub>0.88</sub>Sb<sub>0.12</sub> polycrystal, with a ZT<sub>max</sub> of 0.48 at 150 K, is fabricated and demonstrates a ΔT<sub>max</sub> of 4 K at a T<sub>h</sub> of 75 K. This marks the first report of n-p paired thermoelectric cooling modules operating below liquid nitrogen temperature.
Authors
- Xin Qian (ORCID: https://orcid.org/0000-0002-3198-2014)
- Ronggui Yang (ORCID: https://orcid.org/0000-0002-3602-6945)
- Zhen Lu (ORCID: https://orcid.org/0000-0002-6202-8709)
- Jun Li (ORCID: https://orcid.org/0000-0003-0067-928X)
- Huaizhou Zhao (ORCID: https://orcid.org/0000-0003-4081-7288)
- Hangtian Zhu (ORCID: https://orcid.org/0000-0001-9324-1206)
- Te‐Huan Liu (ORCID: https://orcid.org/0000-0003-2662-2847)
- Xiaowei Wu (ORCID: https://orcid.org/0000-0002-0060-3819)
- Xiaoyan Niu
- Tianyu Wang (ORCID: https://orcid.org/0000-0002-8738-9869)
- Shufang Wang (ORCID: https://orcid.org/0000-0001-5126-9446)
- Nan Chen (ORCID: https://orcid.org/0000-0001-8536-6631)
- Meng Liu (ORCID: https://orcid.org/0000-0002-2921-3697)
- Guodong Li (ORCID: https://orcid.org/0000-0002-1327-0005)
- Zhiliang Li (ORCID: https://orcid.org/0000-0002-8560-9207)
- Zhen Fan
- Qi Zhao (ORCID: https://orcid.org/0000-0001-6750-966X)
- Qiulin Liu
Institutions
- Chinese Academy of Sciences (CN)
- Peking University (CN)
- FZU ‒ Institute of Physics of the Academy of Sciences of the Czech Republic (CZ)
- Institute of Physics (CN)
- National Laboratory for Superconductivity (CN)
- University of Chinese Academy of Sciences (CN)
- Hebei University (CN)
- Huazhong University of Science and Technology (CN)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-04-14
- DOI
- https://doi.org/10.1038/s41467-025-58491-1
- Citations
- 9
- Primary Topic
- Advanced Thermoelectric Materials and Devices
- Type
- article
- Field-Weighted Citation Impact
- 4.66
Funders
- National Natural Science Foundation of China
- Huazhong University of Science and Technology
- National Key Research and Development Program of China