High‐Performance CaMg 2 Bi 2 ‐Based Thermoelectric Materials Driven by Lattice Softening and Orbital Alignment via Cadmium Doping
Advanced Functional Materials, vol. 34
Abstract
Abstract Zintl compounds such as n‐type Mg 3 (Sb,Bi) 2 show promising thermoelectric applications benefiting from their high valley degeneracy and low lattice thermal conductivity. However, the heavier p‐type A Mg 2 X 2 ( A = Ca, and Yb; X = Bi and Sb) Zintl counterparts even exhibit a higher κ lat due to strong chemical bonding. Reducing κ lat of A Mg 2 X 2 is an important route for improving thermoelectric performance. Herein, it is found that Cd doping at the Mg site in CaMg 2 Bi 2 can weaken intralayer covalent bonds and soften acoustic phonons, as well as fill the optical phonon gap. These effects result in large atomic displacement, low phonon group velocity, and strong lattice vibration anharmonicity. Doping 10% Cd leads to a reduction of 56% in the κ lat of CaMg 2 Bi 2 . Moreover, Cd doping promotes orbital alignment and thus increases the density‐of‐states effective mass and Seebeck coefficient. Eventually, in conjunction with carrier concentration optimization by Na doping and band structure engineering by Ba doping, a high ZT of ≈1.3 at 873 K in (Ca 0.85 Ba 0.15 ) 0.995 Na 0.005 Mg 1.85 Cd 0.15 Bi 2 sample is realized. This work highlights the significant role of manipulating chemical bonding in suppressing phonon propagation of semiconductors.
Authors 15
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Harbin Institute of Technology · RWTH Aachen University
Affiliation as printed
Institute of Physics (IA) RWTH Aachen University 52074 Aachen Germany
National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin 150001 China
Institute of Physics (IA), RWTH Aachen University, 52074 Aachen, Germany
National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001 China
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Muchun Guo corresponding
Affiliation as printed
Key Laboratory of materials and surface technology (Ministry of Education) School of Materials Science and Engineering Xihua University Chengdu 610039 China
Key Laboratory of materials and surface technology (Ministry of Education), School of Materials Science and Engineering, Xihua University, Chengdu, 610039 China
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Harbin Institute of Technology
Affiliation as printed
National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin 150001 China
National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001 China
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Affiliation as printed
Key Laboratory of materials and surface technology (Ministry of Education) School of Materials Science and Engineering Xihua University Chengdu 610039 China
Key Laboratory of materials and surface technology (Ministry of Education), School of Materials Science and Engineering, Xihua University, Chengdu, 610039 China
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Affiliation as printed
Key Laboratory of materials and surface technology (Ministry of Education) School of Materials Science and Engineering Xihua University Chengdu 610039 China
Key Laboratory of materials and surface technology (Ministry of Education), School of Materials Science and Engineering, Xihua University, Chengdu, 610039 China
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Affiliation as printed
Key Laboratory of materials and surface technology (Ministry of Education) School of Materials Science and Engineering Xihua University Chengdu 610039 China
Key Laboratory of materials and surface technology (Ministry of Education), School of Materials Science and Engineering, Xihua University, Chengdu, 610039 China
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Affiliation as printed
Key Laboratory of materials and surface technology (Ministry of Education) School of Materials Science and Engineering Xihua University Chengdu 610039 China
Key Laboratory of materials and surface technology (Ministry of Education), School of Materials Science and Engineering, Xihua University, Chengdu, 610039 China
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Affiliation as printed
Key Laboratory of materials and surface technology (Ministry of Education) School of Materials Science and Engineering Xihua University Chengdu 610039 China
Key Laboratory of materials and surface technology (Ministry of Education), School of Materials Science and Engineering, Xihua University, Chengdu, 610039 China
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Harbin Institute of Technology
Affiliation as printed
National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin 150001 China
National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001 China
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Harbin Institute of Technology
Affiliation as printed
National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin 150001 China
National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001 China
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Harbin Institute of Technology
Affiliation as printed
National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin 150001 China
National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001 China
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Harbin Institute of Technology
Affiliation as printed
National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin 150001 China
National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001 China
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Yongsheng Zhang corresponding
Affiliation as printed
Advanced Research Institute of Multidisciplinary Sciences Qufu Normal University Qufu 273165 China
Advanced Research Institute of Multidisciplinary Sciences, Qufu Normal University, Qufu, 273165 China
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Affiliation as printed
Institute of Physics (IA) RWTH Aachen University 52074 Aachen Germany
Institute of Physics (IA), RWTH Aachen University, 52074 Aachen, Germany
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Jiehe Sui corresponding
Harbin Institute of Technology
Affiliation as printed
National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin 150001 China
National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin, 150001 China
Cited by 22 stored of 22
Cited by patents worldwide 1 (Lens.org)
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