首页|Enhancing thermoelectric performance in P-type Mg3Sb2-based Zintls through optimization of band gap structure and nanostructuring

Enhancing thermoelectric performance in P-type Mg3Sb2-based Zintls through optimization of band gap structure and nanostructuring

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P-type Mg3Sb2-based Zintls have attracted considerable interest in the thermoelectric(TE)field due to their environmental friendliness and low cost.However,compared to their n-type counterparts,they show relatively low TE performance,limiting their application in TE devices.In this work,we simul-taneously introduce Bi alloying at Sb sites and Ag doping at Mg sites into the Mg3Sb2 to coopera-tively optimize the electrical and thermal properties for the first time,acquiring the highest ZT value of～0.85 at 723 K and a high average ZT of 0.39 in the temperature range of 323-723 K in sample Mg2.94Ag0.06Sb1.9Bi0.1.The first-principle calculations show that the co-doping of Ag and Bi can shift the Fermi level into the valence band and narrow the band gap,resulting in the increased carrier concentration from 3.50 × 1017 cm-3 in the reference Mg3Sb0.9Bi01 to～7.88 × 1019 cm-3 in sample Mg2.94Ag0.06Sb0.9Bi0.1.As a result,a remarkable power factor of～778.9 μW m-1 K-2 at 723 K is achieved in sample Mg2.94Ag0.06Sb0.9Bi0.1.Meanwhile,a low lattice thermal conductivity of～0.48 Wm-1 K-1 at 723 K is also obtained with the help of phonon scattering at the distorted lattice,point defects,and nano-precipitates in sample Mg2.94Ag0.06Sb0.9Bi0.1.The synergistic effect of using the multi-element co-doping/-alloying to optimize electrical properties in Mg3Sb2 holds promise for further improving the TE performance of Zintl phase materials or even others.

Thermoelectric materialsBand engineeringNanostructuringP-type Mg3Sb2Ag and Bi Co-doping

Yi-bo Zhang、Ji-Sheng Liang、Chengyan Liu、Qi Zhou、Zhe Xu、Hong-bo Chen、Fu-cong Li、Ying Peng、Lei Miao

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Guangxi Key Laboratory of Information Material,Engineering Research Center of Electronic Information Materials and Devices,Ministry of Education,School of Material Science and Engineering,Guilin University of Electronic Technology,Guilin 541004,China

Guangxi Key Laboratory for Relativity Astrophysics,Center on Nanoenergy Research,Guangxi Key Laboratory of Processing for Nonferrous Metal and Featured Materials,School of Physical Science & Technology,Guangxi University,Nanning 530004,China

Guangxi Key Laboratory of Precision Navigation Technology and Application,Guilin University of Electronic Technology,School of Information and Communication,Guilin 541004,China

国家自然科学基金国家自然科学基金国家自然科学基金国家自然科学基金国家重点研发计划Guangxi Science and Technology Planning Project

U21A20545227328552061009522620322022YFE0119100AD21220056

2024

10.1016/j.jmst.2023.05.068

材料科学技术(英文版)
中国金属学会 中国材料研究学会 中国科学院金属研究所

材料科学技术(英文版)

CSTPCD
影响因子：0.657
ISSN：1005-0302
年,卷(期)：2024.170(3)
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