Enhanced Thermoelectric Performance of Zr1-xTaxNiSn Half-Heusler Alloys by Diagonal-rule Doping.
Enhanced Thermoelectric Performance of Zr1-xTaxNiSn Half-Heusler Alloys by Diagonal-rule Doping.
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DOI：
10.1021/acsami.9b21517
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发表时间：
2019-12
影响因子：
9.5
通讯作者：
Xiong Yang;Zhou Jiang;Huijun Kang;Zongning Chen;E. Guo;Daquan Liu;F. Yang;Rengeng Li;
中科院分区：
文献类型：
--
作者：
Xiong Yang;Zhou Jiang;Huijun Kang;Zongning Chen;E. Guo;Daquan Liu;F. Yang;Rengeng Li;
虽然Sb掺杂被认为是最有效的方法来调节载流子浓度在最佳范围内的ZrNiSn基半赫斯勒（HH）合金，所得的热导率仍然很高。因此，本研究的目的是调查的“对角线规则”掺杂的效果，也就是说，Zr的网站被Ta取代，这可以同时提高电导率和降低晶格热导率。Ta在ZrNiSn基体中的固溶度极限被确定为x = 0.04。Zr0.98Ta0.02NiSn在923 K时获得最高的ZT，为0.72。在873 K时，Zr0.98Ta0.02NiSn的ZTavg比ZrNiSn0.99Sb0.01的提高了10.2%，这主要归因于Zr0.98Ta0.02NiSn晶格热导率的降低。这些结果表明，在ZrNiSn基HH合金中，Ta掺杂比Sb掺杂更有效。此外，随着Ta含量的增加，Zr 1-xTaxNiSn的显微硬度显著提高，也远高于其他传统热电材料的显微硬度。
Although Sb doping is regarded as the most effective method to regulate the carrier concentration within the optimum range for ZrNiSn-based half-Heusler (HH) alloys, the resulting thermal conductivity remains high. Hence, the aim of this study was to investigate the effect of "diagonal-rule" doping; that is, the Zr site was displaced by Ta, which can simultaneously enhance the electrical conductivity and reduce the lattice thermal conductivity. The solid-solubility limit of Ta in the ZrNiSn matrix was determined to be x = 0.04. The highest ZT, 0.72, was achieved at 923 K for Zr0.98Ta0.02NiSn. In addition, ZTavg increased by 10.2% for Zr0.98Ta0.02NiSn compared with that for ZrNiSn0.99Sb0.01 at 873 K, which was mainly attributed to the reduced lattice thermal conductivity of Zr0.98Ta0.02NiSn. These results suggest that Ta doping is more effective than Sb doping in ZrNiSn-based HH alloys. In addition, the micro-hardness of Zr1-xTaxNiSn was substantially improved with increasing Ta content and was also much higher than that of other traditional thermoelectric materials.