Volume 19, Issue 44 2303840
Research Article

Mg Compensating Design in the Melting-Sintering Method For High-Performance Mg3(Bi, Sb)2 Thermoelectric Devices

Yali Liu

Yali Liu

College of Materials Science and Engineering, Shenzhen Key Laboratory of Special Functional Materials, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Guangdong Research Center for Interfacial Engineering of Functional Materials, Institute of Deep Underground Sciences and Green Energy, Shenzhen University, Shenzhen, 518060 P. R. China

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Yang Geng

Yang Geng

College of Materials Science and Engineering, Shenzhen Key Laboratory of Special Functional Materials, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Guangdong Research Center for Interfacial Engineering of Functional Materials, Institute of Deep Underground Sciences and Green Energy, Shenzhen University, Shenzhen, 518060 P. R. China

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Yubo Dou

Yubo Dou

College of Materials Science and Engineering, Shenzhen Key Laboratory of Special Functional Materials, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Guangdong Research Center for Interfacial Engineering of Functional Materials, Institute of Deep Underground Sciences and Green Energy, Shenzhen University, Shenzhen, 518060 P. R. China

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Xuelian Wu

Xuelian Wu

College of Materials Science and Engineering, Shenzhen Key Laboratory of Special Functional Materials, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Guangdong Research Center for Interfacial Engineering of Functional Materials, Institute of Deep Underground Sciences and Green Energy, Shenzhen University, Shenzhen, 518060 P. R. China

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Lipeng Hu

Lipeng Hu

College of Materials Science and Engineering, Shenzhen Key Laboratory of Special Functional Materials, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Guangdong Research Center for Interfacial Engineering of Functional Materials, Institute of Deep Underground Sciences and Green Energy, Shenzhen University, Shenzhen, 518060 P. R. China

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Fusheng Liu

Fusheng Liu

College of Materials Science and Engineering, Shenzhen Key Laboratory of Special Functional Materials, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Guangdong Research Center for Interfacial Engineering of Functional Materials, Institute of Deep Underground Sciences and Green Energy, Shenzhen University, Shenzhen, 518060 P. R. China

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Weiqin Ao

Weiqin Ao

College of Materials Science and Engineering, Shenzhen Key Laboratory of Special Functional Materials, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Guangdong Research Center for Interfacial Engineering of Functional Materials, Institute of Deep Underground Sciences and Green Energy, Shenzhen University, Shenzhen, 518060 P. R. China

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Chaohua Zhang

Corresponding Author

Chaohua Zhang

College of Materials Science and Engineering, Shenzhen Key Laboratory of Special Functional Materials, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Guangdong Research Center for Interfacial Engineering of Functional Materials, Institute of Deep Underground Sciences and Green Energy, Shenzhen University, Shenzhen, 518060 P. R. China

E-mail: [email protected]

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First published: 28 June 2023
Citations: 18

Abstract

N-type Mg3(Bi, Sb)2-based thermoelectric (TE) alloys show great promise for solid-state power generation and refrigeration, owing to their excellent figure-of-merit (ZT) and using cheap Mg. However, their rigorous preparation conditions and poor thermal stability limit their large-scale applications. Here, this work develops an Mg compensating strategy to realize n-type Mg3(Bi, Sb)2 by a facile melting-sintering approach. “2D roadmaps” of TE parameters versus sintering temperature and time are plotted to understand the Mg-vacancy-formation and Mg-diffusion mechanisms. Under this guidance, high weight mobility of 347 cm2 V−1 s−1 and power factor of 34 µW cm−1 K−2 can be obtained for Mg3.05Bi1.99Te0.01, and a peak ZT≈1.55 at 723 K and average ZT≈1.25 within 323–723 K can be obtained for Mg3.05(Sb0.75Bi0.25)1.99Te0.01. Moreover, this Mg compensating strategy can also improve the interfacial connecting and thermal stability of corresponding Mg3(Bi, Sb)2/Fe TE legs. As a consequence, this work fabricates an 8-pair Mg3Sb2-GeTe-based power-generation device reaching an energy conversion efficiency of ≈5.0% at a temperature difference of 439 K, and a one-pair Mg3Sb2-Bi2Te3-based cooling device reaching −10.7 °C at the cold side. This work paves a facile way to obtain Mg3Sb2-based TE devices at low cost and also provides a guide to optimize the off-stoichiometric defects in other TE materials.

Conflict of Interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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