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Rattling-like behavior and band convergence induced ultra-low lattice thermal conductivity in MgAl_(2)Te_(4) monolayer

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Journal of Materiomics 2024年第5期10卷 1004-1016页

作者： Da Wan Shulin Bai Xiaodong Li Jingyi Zhang Peng Ai Wanrong Guo Shuwei Tang College of Materials Science and Engineering Liaoning Technical UniversityFuxinLiaoning123000China Faculty of Chemistry Northeast Normal UniversityChangchunJilin130024China

Inspired by the excellent stability exhibited by experimentally synthesized two-dimensional(2D)MoSi_(2)N_(4) layered material,the thermal and electronic transport,and thermoelectric(TE)properties of MgAl2Te4 monolayer are systematically investigated using the First-principles calculations and Boltzmann transport *** mechanical stability,dynamic stability,and thermal stability(900 K)of the MgAl_(2)Te_(4) monolayer are demonstrated,*** MgAl_(2)Te_(4) monolayer exhibits a bandgap of 1.35 eV using the HSE06 functional in combination with spin-orbit coupling(SOC)*** convergence in the valence band is favorable to improve the thermoelectric *** rattling thermal damping effect caused by the weak bonding of Mgsingle bondTe bonds in MgAl2Te4 monolayer leads to ultra-low lattice thermal conductivity(0.95/0.38 W/(m·K)@300 K along the x-/y-direction),which is further demonstrated by the phonon group velocities,phonon relaxation time,Grüneisen parameters,and scattering *** optimal zT of 3.28 at 900 K is achieved for the p-type MgAl_(2)Te_(4) monolayer,showing the great promising prospect for the excellent p-type thermoelectric *** current work not only reveals the underlying mechanisms responsible for the excellent TE properties,but also elaborates on the promising thermoelectric application of MgAl_(2)Te_(4) monolayer material at high temperature.

关键词： Thermoelectric material Mg atomic rattling band convergence Ultra-low lattice thermal conductivity

band modification towards high thermoelectric performance of SnSb_(2)Te_(4) with strong anharmonicity driven by cation disorder

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Journal of Materials Science & Technology 2023年第23期154卷 140-148页

作者： Hong Wu Peng Chen Zizhen Zhou De Zhang Xiangnan Gong Bin Zhang Yang Zhou Kunling Peng Yanci Yan Guiwen Wang Jun Liu Dengfeng Li Guang Han Guoyu Wang Xu Lu Xiaoyuan Zhou School of Science Chongqing University of Posts and Telecommunications Chongqing 400065 China College of Physics and Center for Quantum Materials & Devices Chongqing University Chongqing 401331 China College of Materials Science and Engineering Chongqing University Chongqing 400044 China Chongqing Institute of Green and Intelligent Technology Chinese Academy of Sciences Chongqing 400714 China Analytical and Testing Center of Chongqing University Chongqing 401331 China Interdisciplinary Center for Fundamental and Frontier Sciences Nanjing University of Science and Technology Jiangyin 214443 China

As a typical (IV–VI)_(x)(V_(2)VI_(3))_(y) compound, the tetradymite-like layered SnSb_(2)Te_(4) -based compounds have attracted increasing attention in the thermoelectric community owing to the intrinsically low lattice thermal conductivity. Nevertheless, the effect of cations disorder on the inherent physical characteristics remains puzzling, and its inferior Seebeck coefficient is the bottleneck to achieving high thermoelectric performance. In this work, the thermoelectric properties of polycrystalline In_(x)Sn_(1−x)Sb_(2)(Te_(1−y)Se_(y))_(4) (0≤x≤0.1,0≤y≤0.15) samples are comprehensively investigated. In conjunction with the calculated band structure and experimental results, the Seebeck coefficient and power factor are markedly improved after the introduction of indium and selenium, which originates from the combined effects of the emergent resonant states and converged valence bands along with optimal carrier concentration. Additionally, compared with the ordered lattice structure, the disordered cations occupancy in SnSb_(2)Te_(4) further strengthens lattice anharmonicity and reduces phonon group velocity verified by first-principles calculations, securing intrinsically low lattice thermal conductivity. Finally, a record zT value of ∼0.6 at 670 K and an average zT of ∼0.4 between 320 and 720 K are obtained in the In0.1 Sn0.9 Sb2 Te3.4 Se0.6 sample, being one of the highest zT values among SnSb2 Te4 -based materials. This work not only demonstrates that SnSb2 Te4 -based compounds are promising thermoelectric candidates, but also provides guidance for the promotion of thermoelectric performance in a broad temperature range.

关键词： Thermoelectric SnSb_(2)Te_(4) Lattice anharmonicity Resonant level band convergence

Substantial thermoelectric enhancement achieved by manipulating the band structure and dislocations in Ag and La co-doped SnTe

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Journal of Advanced Ceramics 2021年第4期10卷 860-870页

作者： Wenjing XU Zhongwei ZHANG Chengyan LIU Jie GAO Zhenyuan YE Chunguang CHEN Ying PENG Xiaobo BAI Lei MIAO Guangxi Key Laboratory of Information Material Guangxi Collaborative Innovation Center of Structure and Property for New Energy and MaterialsSchool of Material Science and EngineeringGuilin University of Electronic TechnologyGuilin 541004China Department of Materials Science and Engineering SIT Research LaboratoriesInnovative Global ProgramFaculty of EngineeringShibaura Institute of TechnologyTokyo 135-8548Japan

Eco-friendly SnTe based thermoelectric materials are intensively studied recently as candidates to replace PbTe;yet the thermoelectric performance of SnTe is suppressed by its intrinsically high carrier concentration and high thermal *** this work,we confirm that the Ag and La co-doping can be applied to simultaneously enhance the power factor and reduce the thermal conductivity,contributing to a final promotion of figure of *** one hand,the carrier concentration and band offset between valence bands are concurrently reduced,promoting the power factor to a highest value of-2436μW·m^(-1)·K^(-2) at 873 *** the other hand,lots of dislocations(~3.16×10^(7)mm^(-2))associated with impurity precipitates are generated,resulting in the decline of thermal conductivity to a minimum value of 1.87 W·m^(-1)·K^(-1) at 873 *** a result,a substantial thermoelectric performance enhancement up to zT≈1.0 at 873 K is obtained for the sample Sn0.94Ag0.09La0.05Te,which is twice that of the pristine SnTe(zT≈0.49 at 873 K).This strategy of synergistic manipulation of electronic band and microstructures via introducing rare earth elements could be applied to other systems to improve thermoelectric performance.

关键词： SnTe band convergence dislocation Ag and La co-doping thermoelectric performance

Eco-friendly high-performance silicide thermoelectric materials

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National Science Review 2017年第4期4卷 611-626页

作者： Wei Liu Kang Yin Qingjie Zhang Ctirad Uher Xinfeng Tang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Department of Physics University of Michigan

Silicide-based thermoelectrics are examples of cost-efficient and environmentally friendly new energy materials, which can be used for power-generation applications in the range of 500–800 K. We review the research focusing on the exploration of n-type Mg2IV-based solid solutions(IV = Si, Ge and Sn) and summarize the most prominent discoveries achieved so far in their studies. Owing to their superior performance compared to other silicides, including p-type Mg2IV, higher manganese silicides(HMS) are commonly considered as a suitable p-type material to be used in thermoelectric modules in conjunction with n-type Mg2IV-based solid solutions for mid-temperature power-generation applications. We describe the strategies used to improve the thermal and electronic transport properties of n-type Mg2IV-based solid solutions and mention some key features of HMS. We also point out the importance of mechanical properties and thermal stability of this family of materials and offer perspectives on the future research work to further improve their performance.

关键词： silicides band convergence carrier doping composition manipulation mechanical properties thermal stability

Enhanced thermoelectric performance of Sb-doped Mg_(2)Si_(0.4)Sn_(0.6)via doping,alloying and nanoprecipitation

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Journal of Materiomics 2024年第2期10卷 285-292页

作者： Binhao Wang Haidong Zhao Jianghua Li Bin Zhang Dan Wang Chen Chen Aihua Song Wentao Hu Dongli Yu Bo Xu Yongjun Tian Center for High Pressure Science State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdaoHebei066004China Shaanxi University of Technology HanzhongShaanxi723000China

With the advantages of eco-friendliness,low cost,and low density,Mg_(2)(Si,Sn)solid solutions are promising candidates for thermoelectric *** this work,Sb-doped Mg_(2)Si_(0.4)Sn_(0.6)bulks were prepared with a combined method of solid-state reaction and high pressure synthesis,followed by spark plasma *** investigations show that Sb doping optimizes the carrier concentration,while Si/Sn alloying effectively suppresses the lattice thermal conductivity and induces a convergence of the two lowest-lying conduction ***,numerous coherent Sn-rich nanoprecipitates are formed within micron-sized *** these factors contribute synergistically to improving the thermoelectric properties of Mg_(2)Si_(0.4)Sn_(0.6).The optimal Mg_(2)(Si_(0.4)Sn_(0.6))_(0.985)Sb_(0.015)exhibits a power factor higher than 4000 mW·m^(-1)·K^(-2)and a lattice thermal conductivity less than 0.8 W·m^(-1)·K^(-1)at temperatures higher than 600 K,leading to the highest ZT of 1.61 at 823 *** work demonstrates an effective approach to enhancing the thermoelectric performance of n-type Mg_(2)X solid solutions through doping,alloying,and microstructure modification.

关键词： Magnesium silicide High pressure synthesis Alloy scattering band convergence