High-Performance Thermoelectrics α-Ag9Ga1-xTe6 Compounds with Ultra-low Lattice Thermal Conductivity Originating from Ag9Te2 Motifs.
High-Performance Thermoelectrics α-Ag9Ga1-xTe6 Compounds with Ultra-low Lattice Thermal Conductivity Originating from Ag9Te2 Motifs.
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源自 Ag9Te2 基序的具有超低晶格热导率的高性能热电 α-Ag9Ga1-xTe6 化合物。
DOI：
10.1002/anie.202208281
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发表时间：
2022
影响因子：
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通讯作者：
Xinfeng Tang
中科院分区：
文献类型：
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作者：
Ying Tang;Yimeng Yu;Na Zhao;Keke Liu;Haijie Chen;C. Stoumpos;Yixuan Shi;Shuo Chen;Lingxiao Yu;Jinsong Wu;Qingjie Zhang;X. Su;Xinfeng Tang
我们测定了具有六方晶格的高温α-Ag9 Gate 6相的复杂原子结构(P6 3mC空间群，a=b=8.2766？，c=13.4349？)该结构具有外部的[Gate 4]5-四面体和内部的[Ag9Te2]5+团簇。所有的银离子都无序地分布在晶格中，其中7个银原子组成了笼状的[Ag9Te2]5+团簇。高度无序的银离子非谐振动，产生了低频光学声子和声学声子之间的强耦合。再加上S的1354m声速，使得Ag9Ga0.95Te6在673K时的热导率仅为0.20Wm-1K-1，而Ga9Ga0.91Te6的缺位有效地优化了其电输运性质，即Ag9Ga0.91Te6样品在673K时的功率因数达到0.40 mW m-1K-2，这使得Ag9Ga0.95Te6在623K时的ZT值达到1.13。这比原始的Ag9 Gate 6样品高出41%。
We have determined the complex atomic structure of high-temperature α-Ag 9 GaTe 6 phase with a hexagonal lattice ( P 6 3 mc space group, a = b = 8.2766 Å, c = 13.4349 Å). The structure has the outer [GaTe 4 ] 5 - tetrahedrons and the inner [Ag 9 Te 2 ] 5+ clusters. All of the Ag ions distribute in the lattice disorderly, of which seven Ag atoms constitute the cage-like [Ag 9 Te 2 ] 5+ clusters. The highly disordered Ag ions vibrate in-harmonically, producing the strong coupling between low frequency optical phonon and acoustic phonon. This in conjunction with low sound velocity of 1354 m s -1 leads to an ultralow thermal conductivity of 0.20 W m -1 K -1 at 673 K. Meanwhile, the deficiency of Ga in Ag 9 Ga 1-x Te 6 compounds effectively optimizes the electronic transport properties, i.e. Ag 9 Ga 0.91 Te 6 sample attains the highest power factor of 0.40 mW m -1 K -2 at 673 K. All these contribute to a much-improved ZT value of 1.13 at 623 K for Ag 9 Ga 0.95 Te 6 , which is 41% higher than that of the pristine Ag 9 GaTe 6 sample.