Direct Observation of Inherent Atomic-Scale Defect Disorders responsible for High-Performance Ti1− xHfxNiSn1− ySby Half-Heusler Thermoelectric Alloys

Ki Sung Kim, Young Min Kim, Hyeona Mun, Jisoo Kim, Jucheol Park, Albina Y. Borisevich, Kyu Hyoung Lee, Sung Wng Kim

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Structural defects often dominate the electronic- and thermal-transport properties of thermoelectric (TE) materials and are thus a central ingredient for improving their performance. However, understanding the relationship between TE performance and the disordered atomic defects that are generally inherent in nanostructured alloys remains a challenge. Herein, the use of scanning transmission electron microscopy to visualize atomic defects directly is described and disordered atomic-scale defects are demonstrated to be responsible for the enhancement of TE performance in nanostructured Ti1− xHfxNiSn1− ySby half-Heusler alloys. The disordered defects at all atomic sites induce a local composition fluctuation, effectively scattering phonons and improving the power factor. It is observed that the Ni interstitial and Ti,Hf/Sn antisite defects are collectively formed, leading to significant atomic disorder that causes the additional reduction of lattice thermal conductivity. The Ti1− xHfxNiSn1− ySby alloys containing inherent atomic-scale defect disorders are produced in one hour by a newly developed process of temperature-regulated rapid solidification followed by sintering. The collective atomic-scale defect disorder improves the zT to 1.09 ± 0.12 at 800 K for the Ti0.5Hf0.5NiSn0.98Sb0.02 alloy. These results provide a promising avenue for improving the TE performance of state-of-the-art materials.

Original languageEnglish
Article number1702091
JournalAdvanced Materials
Volume29
Issue number36
DOIs
Publication statusPublished - 2017 Sep 27

Fingerprint

Defects
Rapid solidification
Phonons
Transport properties
Thermal conductivity
Sintering
Scattering
Transmission electron microscopy
Scanning electron microscopy
Chemical analysis
Temperature

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Kim, Ki Sung ; Kim, Young Min ; Mun, Hyeona ; Kim, Jisoo ; Park, Jucheol ; Borisevich, Albina Y. ; Lee, Kyu Hyoung ; Kim, Sung Wng. / Direct Observation of Inherent Atomic-Scale Defect Disorders responsible for High-Performance Ti1− xHfxNiSn1− ySby Half-Heusler Thermoelectric Alloys. In: Advanced Materials. 2017 ; Vol. 29, No. 36.
@article{a56d6ea9e8514a6a99ebfffc27a5d7a9,
title = "Direct Observation of Inherent Atomic-Scale Defect Disorders responsible for High-Performance Ti1− xHfxNiSn1− ySby Half-Heusler Thermoelectric Alloys",
abstract = "Structural defects often dominate the electronic- and thermal-transport properties of thermoelectric (TE) materials and are thus a central ingredient for improving their performance. However, understanding the relationship between TE performance and the disordered atomic defects that are generally inherent in nanostructured alloys remains a challenge. Herein, the use of scanning transmission electron microscopy to visualize atomic defects directly is described and disordered atomic-scale defects are demonstrated to be responsible for the enhancement of TE performance in nanostructured Ti1− xHfxNiSn1− ySby half-Heusler alloys. The disordered defects at all atomic sites induce a local composition fluctuation, effectively scattering phonons and improving the power factor. It is observed that the Ni interstitial and Ti,Hf/Sn antisite defects are collectively formed, leading to significant atomic disorder that causes the additional reduction of lattice thermal conductivity. The Ti1− xHfxNiSn1− ySby alloys containing inherent atomic-scale defect disorders are produced in one hour by a newly developed process of temperature-regulated rapid solidification followed by sintering. The collective atomic-scale defect disorder improves the zT to 1.09 ± 0.12 at 800 K for the Ti0.5Hf0.5NiSn0.98Sb0.02 alloy. These results provide a promising avenue for improving the TE performance of state-of-the-art materials.",
author = "Kim, {Ki Sung} and Kim, {Young Min} and Hyeona Mun and Jisoo Kim and Jucheol Park and Borisevich, {Albina Y.} and Lee, {Kyu Hyoung} and Kim, {Sung Wng}",
year = "2017",
month = "9",
day = "27",
doi = "10.1002/adma.201702091",
language = "English",
volume = "29",
journal = "Advanced Materials",
issn = "0935-9648",
publisher = "Wiley-VCH Verlag",
number = "36",

}

Direct Observation of Inherent Atomic-Scale Defect Disorders responsible for High-Performance Ti1− xHfxNiSn1− ySby Half-Heusler Thermoelectric Alloys. / Kim, Ki Sung; Kim, Young Min; Mun, Hyeona; Kim, Jisoo; Park, Jucheol; Borisevich, Albina Y.; Lee, Kyu Hyoung; Kim, Sung Wng.

In: Advanced Materials, Vol. 29, No. 36, 1702091, 27.09.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Direct Observation of Inherent Atomic-Scale Defect Disorders responsible for High-Performance Ti1− xHfxNiSn1− ySby Half-Heusler Thermoelectric Alloys

AU - Kim, Ki Sung

AU - Kim, Young Min

AU - Mun, Hyeona

AU - Kim, Jisoo

AU - Park, Jucheol

AU - Borisevich, Albina Y.

AU - Lee, Kyu Hyoung

AU - Kim, Sung Wng

PY - 2017/9/27

Y1 - 2017/9/27

N2 - Structural defects often dominate the electronic- and thermal-transport properties of thermoelectric (TE) materials and are thus a central ingredient for improving their performance. However, understanding the relationship between TE performance and the disordered atomic defects that are generally inherent in nanostructured alloys remains a challenge. Herein, the use of scanning transmission electron microscopy to visualize atomic defects directly is described and disordered atomic-scale defects are demonstrated to be responsible for the enhancement of TE performance in nanostructured Ti1− xHfxNiSn1− ySby half-Heusler alloys. The disordered defects at all atomic sites induce a local composition fluctuation, effectively scattering phonons and improving the power factor. It is observed that the Ni interstitial and Ti,Hf/Sn antisite defects are collectively formed, leading to significant atomic disorder that causes the additional reduction of lattice thermal conductivity. The Ti1− xHfxNiSn1− ySby alloys containing inherent atomic-scale defect disorders are produced in one hour by a newly developed process of temperature-regulated rapid solidification followed by sintering. The collective atomic-scale defect disorder improves the zT to 1.09 ± 0.12 at 800 K for the Ti0.5Hf0.5NiSn0.98Sb0.02 alloy. These results provide a promising avenue for improving the TE performance of state-of-the-art materials.

AB - Structural defects often dominate the electronic- and thermal-transport properties of thermoelectric (TE) materials and are thus a central ingredient for improving their performance. However, understanding the relationship between TE performance and the disordered atomic defects that are generally inherent in nanostructured alloys remains a challenge. Herein, the use of scanning transmission electron microscopy to visualize atomic defects directly is described and disordered atomic-scale defects are demonstrated to be responsible for the enhancement of TE performance in nanostructured Ti1− xHfxNiSn1− ySby half-Heusler alloys. The disordered defects at all atomic sites induce a local composition fluctuation, effectively scattering phonons and improving the power factor. It is observed that the Ni interstitial and Ti,Hf/Sn antisite defects are collectively formed, leading to significant atomic disorder that causes the additional reduction of lattice thermal conductivity. The Ti1− xHfxNiSn1− ySby alloys containing inherent atomic-scale defect disorders are produced in one hour by a newly developed process of temperature-regulated rapid solidification followed by sintering. The collective atomic-scale defect disorder improves the zT to 1.09 ± 0.12 at 800 K for the Ti0.5Hf0.5NiSn0.98Sb0.02 alloy. These results provide a promising avenue for improving the TE performance of state-of-the-art materials.

UR - http://www.scopus.com/inward/record.url?scp=85025428064&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85025428064&partnerID=8YFLogxK

U2 - 10.1002/adma.201702091

DO - 10.1002/adma.201702091

M3 - Article

AN - SCOPUS:85025428064

VL - 29

JO - Advanced Materials

JF - Advanced Materials

SN - 0935-9648

IS - 36

M1 - 1702091

ER -