Enhancement of Thermoelectric Figure of Merit of p‐Type Nb0.9Ti0.1FeSb Half‐Heusler Compound by Nanostructuring,Physica Status Solidi (A) - Applications and Materials Science

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Enhancement of Thermoelectric Figure of Merit of p‐Type Nb0.9Ti0.1FeSb Half‐Heusler Compound by Nanostructuring
Physica Status Solidi (A) - Applications and Materials Science Pub Date : 2020-09-29 , DOI: 10.1002/pssa.202000419
Wanthana Silpawilawan _{1,

2} , Sora-at Tanuslip ₃ , Yuji Ohishi ₁ , Hiroaki Muta ₁ , Ken Kurosaki _{1,

3,

4}

Affiliation

Half‐Heusler compounds with 18 valence electron count show a large thermoelectric power factor. However, the thermal conductivity is high, so if the thermal conductivity can be reduced, the thermoelectric figure of merit zT can be enhanced. The key point to reduce the thermal conductivity is effective phonon scattering. Nanostructuring is a well‐known method of introducing phonon scattering centers by creating high‐density grain boundaries in nanoscale. Herein, NbFeSb, which is one of the best p‐type half‐Heusler compounds in thermoelectrics, is focused on. Nanostructured bulk Nb_0.9Ti_0.1FeSb is synthesized by melt spinning followed by spark plasma sintering. The cooling speed during melt spinning is changed to obtain nanostructures with different sizes. This study reveals that the zT at high temperatures is enhanced by nanostructuring. The nanostructured Nb_0.9Ti_0.1FeSb shows an ≈20% higher zT value at 1073 K than the non‐nanostructured one, mainly due to the effective reduction of the thermal conductivity.

中文翻译：

通过纳米结构增强p型Nb0.9Ti0.1FeSb半霍斯勒化合物的热电品质因数

具有18个价电子数的半霍斯勒化合物显示出较大的热电功率因数。但是，热导率高，因此，如果可以降低热导率，则可以提高热电品质因数zT。降低导热系数的关键是有效的声子散射。纳米结构是通过创建纳米级高密度晶界来引入声子散射中心的众所周知的方法。本文重点介绍了NbFeSb，它是热电学中最好的p型半霍斯勒化合物之一。纳米大块Nb _0.9 Ti _0.1FeSb是通过熔融纺丝，然后进行火花等离子体烧结合成的。改变熔融纺丝过程中的冷却速度以获得具有不同尺寸的纳米结构。这项研究表明，纳米结构提高了高温下的zT。纳米结构的Nb _0.9 Ti _0.1 FeSb在1073 K处的zT值比非纳米结构的Nb _0.9 Ti _0.1 FeSb高20％左右，这主要是由于有效降低了热导率。

更新日期：2020-12-04

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