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Enhanced Thermoelectric Efficiency in P-Type Mg3Sb2: Role of Monovalent Atoms Codoping at Mg sites
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2023-04-17 , DOI: 10.1021/acsami.3c02151
Minati Tiadi 1, 2 , Vikrant Trivedi 1, 3 , Santosh Kumar 2 , P K Jain 4 , Satyesh Kumar Yadav 5 , R Gopalan 1, 3 , Dillip K Satapathy 2 , Manjusha Battabyal 1
Affiliation  

Due to natural abundance, low cost, and compatibility with sustainable green technology, Mg3Sb2-based Zintl compounds are comprehensively explored as potential thermoelectric materials for near-room temperature applications. The effective use of these materials in thermoelectric devices requires both p and n-type Mg3Sb2 having comparable thermoelectric efficiency. However, p-type Mg3Sb2 has inferior thermoelectric efficiency efficiency compared to its n-type counterpart due to low electrical conductivity (103Sm1). Here, we show that codoping of monovalent atoms (Li–Ag, and Na–Ag) at the Mg site of Mg3Sb2 produces a synergistic effect and boosts the electrical conductivity, which enhances the thermoelectric properties of p-type Mg3Sb2. While, Ag prefers to occupy the Mg2 site, Li and Na are favorable at the Mg1 site of Mg3Sb2 lattice. Compared to Li–Ag codoping, Na–Ag codoping in Mg3Sb2 is found to be more effective for increasing the charge carrier concentration and significantly augmenting the electrical conductivity. The dominance of the three-phonon scattering mechanism in Li and Li–Ag doped Mg3Sb2 and the four-phonon scattering process for the Na and Na–Ag doped Mg3Sb2 are confirmed. Due to the simultaneous increase in electrical conductivity and decrease in thermal conductivity, the zT value ∼0.8 at 675 K achieved for Mg2.975Na0.02Ag0.005Sb2 is the highest value among p-type Mg3Sb2. Our work shows a constructive approach to enhance the zT of p-type Mg3Sb2 via monovalent atoms codoping at the Mg sites.

中文翻译:

P 型 Mg3Sb2 中增强的热电效率:单价原子在 Mg 位置共掺杂的作用

由于天然丰富、成本低以及与可持续绿色技术的兼容性,基于 Mg 3 Sb 2的 Zintl 化合物被广泛探索作为近室温应用的潜在热电材料。这些材料在热电装置中的有效使用需要具有相当热电效率的p 型和 n 型 Mg 3 Sb 2 。然而,由于低电导率,p 型 Mg 3 Sb 2与其 n 型对应物相比具有较差的热电效率(~103个小号1个). 在这里,我们表明在 Mg 3 Sb 2的 Mg 位置共掺杂单价原子(Li-Ag 和 Na-Ag)会产生协同效应并提高电导率,从而增强 p 型 Mg 3 Sb的热电性能2 . 而Ag更倾向于占据Mg2位,而Li和Na更倾向于占据Mg 3 Sb 2晶格的Mg1位。与 Li-Ag 共掺杂相比,Mg 3 Sb 2中的 Na-Ag 共掺杂被发现可以更有效地增加载流子浓度并显着提高电导率。三声子散射机制在 Li 和 Li-Ag 掺杂 Mg 3 Sb 2中的主导地位并且证实了Na 和 Na-Ag 掺杂的 Mg 3 Sb 2的四声子散射过程。由于电导率同时增加和热导率降低, Mg 2.975 Na 0.02 Ag 0.005 Sb 2在675 K时的zT值~0.8是p型Mg 3 Sb 2中最高的值。我们的工作展示了一种通过在 Mg 位点共掺杂单价原子来增强p 型 Mg 3 Sb 2的zT的建设性方法。
更新日期:2023-04-17
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