无机材料学报

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纳米复合MgAgSb基合金的热电输运性能优化

吴华鑫1, 张骐昊2, YANHaixue3, 王连军1, 江莞1,2   

  1. 1.东华大学 先进纤维材料全国重点实验室 材料科学与工程学院, 上海 201620;
    2.东华大学 功能材料研究中心, 上海 201620;
    3.School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
  • 收稿日期:2025-01-08 修回日期:2025-03-29
  • 作者简介:吴华鑫(2000-), 男, 硕士研究生. E-mail: wuhuaxin2163@163.com
  • 基金资助:
    国家自然科学基金(U23A20685); 上海市教委科研创新项目(2021-01-07-00-03-E00110); 上海市科委项目(23520710300)

Optimization of Thermoelectric Transport Properties in Nanocomposite MgAgSb-Based Alloys

WU Huaxin1, ZHANG Qihao2, YAN Haixue3, WANG Lianjun1, JIANG Wan1,2   

  1. 1. State Key Laboratory of Advanced Fiber Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620, China;
    2. China Institute of Functional Materials, Donghua University, Shanghai 201620, China;
    3. School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK
  • Received:2025-01-08 Revised:2025-03-29
  • About author:WU Huaxin (2000–), male, Master candidate. E-mail: wuhuaxin2163@163.com
  • Supported by:
    National Natural Science Foundation of China (62105132); Scientific Research Fund Project of Education Department of Liaoning Province (LJ212410148055 and LJ212410148058)

摘要: MgAgSb在近室温区间(300~573 K)表现出良好的热电性能,近年来成为p型材料的重点研究对象。由于原子掺杂水平较低,仅采用掺杂手段优化载流子浓度,热电性能的增幅有限。本研究选择在MgAg0.97Sb0.99基体材料中分别引入Nb和Ta纳米第二相,通过高能球磨机械合金化的方法制备了xNb/MgAg0.97Sb0.99yTa/MgAg0.97Sb0.99两种系列合金。引入Nb纳米第二相显著改变了材料的载流子和声子输运特性。0.005Nb/MgAg0.97Sb0.99合金中由于存在纳米第二相Nb,其特殊的微观结构优化了电学性能,该合金在533 K最高功率因子为24.1 μW·cm-1·K-2。同时,引入的Nb第二相增加了声子散射,从而显著降低了热导率,最终0.005Nb/MgAg0.97Sb0.99样品的zT在483 K时达到的最优1.09,相较于MgAg0.97Sb0.99样品提升了约9.0%。此外,在MgAg0.97Sb0.99样品中引入Nb的同族元素Ta,产生的影响与Nb近似,0.005Ta/MgAg0.97Sb0.99样品在483 K的zT达到为1.02。这项研究展示了一种有效的纳米复合策略,能够优化热电输运性能并提高p型MgAg0.97Sb0.99的热电性能。

关键词: MgAgSb基化合物, 第二相, 合金化, 热电性能

Abstract: MgAgSb exhibits excellent thermoelectric performance in the near-room temperature range (300-573K), making it a key research focus for p-type materials in recent years. Due to the low level of atomic doping, the improvement of thermoelectric performance through carrier concentration optimization via doping alone is limited. In this study, Nb and Ta nano-secondary phases were introduced into the MgAg0.97Sb0.99 matrix, and two series of alloys, xNb/MgAg0.97Sb0.99 and yTa/MgAg0.97Sb0.99, were prepared using high-energy ball milling mechanical alloying. The introduction of the Nb nano-secondary phase significantly altered the carrier and phonon transport properties of the material. Due to the presence of the nano-secondary phase Nb in the 0.005Nb/MgAg0.97Sb0.99 alloy, its unique microstructure optimized the electrical performance, achieving a maximum power factor of 24.1 μW·cm-1·K-2 at 533 K. Additionally, the introduction of the secondary phase enhanced phonon scattering, significantly reducing thermal conductivity. As a result, the 0.005Nb/MgAg0.97Sb0.99 sample achieved the optimal zT of 1.09 at 483 K, improved by ~9.0% compared to MgAg0.97Sb0.99 at the same temperature. Furthermore, the introduction of Ta, a homologue of Nb, into the MgAg0.97Sb0.99 sample showed a similar trend, with 0.005Ta/MgAg0.97Sb0.99 achieving zT of 1.02 at 483 K. This study demonstrates an effective nanocomposite strategy for optimizing thermoelectric transport properties and enhancing the thermoelectric performance of p-type MgAg0.97Sb0.99.

Key words: MgAgSb-based compound, secondary phase, alloying, thermoelectric performance

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