Thermoelectric Properties and Electronic Structures of CuTi 2 S 4 Thiospinel and Its Derivatives

Structural Design for Spinel-Related Thermoelectric Materials

Katsuaki Hashikuni, Koichiro Suekuni, Hidetomo Usui, Raju Chetty, Michihiro Ohta, Kazuhiko Kuroki, Toshiro Takabatake, Kosuke Watanabe, Michitaka Ohtaki

研究成果: ジャーナルへの寄稿記事

1 引用 (Scopus)

抄録

We report the preparations, thermoelectric and magnetic properties, and electronic structures of Cu-Ti-S systems, namely, cubic thiospinel c-Cu 1-x Ti 2 S 4 (x ≤ 0.375), a derivative cubic and Ti-rich phase c-Cu 1-x Ti 2.25 S 4 (x = 0.5, 0.625), and a rhombohedral phase r-CuTi 2 S 4 . All samples have the target compositions except for r-CuTi 2 S 4 , whose actual composition is Cu 1.14 Ti 1.80 S 4 . All of the phases have n-type metallic character and exhibit Pauli paramagnetism, as proven by experiments and first-principles calculations. The Cu and Ti deficiencies in c-Cu 1-x Ti 2 S 4 and r-CuTi 2 S 4 , respectively, decrease the electron-carrier concentration, whereas the "excess" of Ti ions in c-Cu 1-x Ti 2.25 S 4 largely increases it. For r-CuTi 2 S 4 , the reduced carrier concentration increases the electrical resistivity and Seebeck coefficient, leading to the highest thermoelectric power factor of 0.5 mW K -2 m -1 at 670 K. For all of the Cu-Ti-S phases, the thermal conductivity at 670 K is 3.5-5 W K -1 m -1 , where the lattice part of the conductivity is as low as 1 W K -1 m -1 at 670 K. As a result, r-CuTi 2 S 4 shows the highest dimensionless thermoelectric figure of merit ZT of 0.2. The present systematic study on the Cu-Ti-S systems provides insights into the structural design of thermoelectric materials based on Cu-M-S (M = transition-metal elements).

元の言語英語
ページ(範囲)1425-1432
ページ数8
ジャーナルInorganic Chemistry
58
発行部数2
DOI
出版物ステータス出版済み - 1 22 2019

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structural design
thermoelectric materials
Structural design
spinel
Electronic structure
Carrier concentration
electronic structure
Derivatives
Paramagnetism
Seebeck coefficient
paramagnetism
Thermoelectric power
Seebeck effect
Chemical analysis
figure of merit
Chemical elements
Transition metals
Thermal conductivity
Magnetic properties
thermal conductivity

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

これを引用

Thermoelectric Properties and Electronic Structures of CuTi 2 S 4 Thiospinel and Its Derivatives : Structural Design for Spinel-Related Thermoelectric Materials. / Hashikuni, Katsuaki; Suekuni, Koichiro; Usui, Hidetomo; Chetty, Raju; Ohta, Michihiro; Kuroki, Kazuhiko; Takabatake, Toshiro; Watanabe, Kosuke; Ohtaki, Michitaka.

:: Inorganic Chemistry, 巻 58, 番号 2, 22.01.2019, p. 1425-1432.

研究成果: ジャーナルへの寄稿記事

Hashikuni, Katsuaki ; Suekuni, Koichiro ; Usui, Hidetomo ; Chetty, Raju ; Ohta, Michihiro ; Kuroki, Kazuhiko ; Takabatake, Toshiro ; Watanabe, Kosuke ; Ohtaki, Michitaka. / Thermoelectric Properties and Electronic Structures of CuTi 2 S 4 Thiospinel and Its Derivatives : Structural Design for Spinel-Related Thermoelectric Materials. :: Inorganic Chemistry. 2019 ; 巻 58, 番号 2. pp. 1425-1432.
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title = "Thermoelectric Properties and Electronic Structures of CuTi 2 S 4 Thiospinel and Its Derivatives: Structural Design for Spinel-Related Thermoelectric Materials",
abstract = "We report the preparations, thermoelectric and magnetic properties, and electronic structures of Cu-Ti-S systems, namely, cubic thiospinel c-Cu 1-x Ti 2 S 4 (x ≤ 0.375), a derivative cubic and Ti-rich phase c-Cu 1-x Ti 2.25 S 4 (x = 0.5, 0.625), and a rhombohedral phase r-CuTi 2 S 4 . All samples have the target compositions except for r-CuTi 2 S 4 , whose actual composition is Cu 1.14 Ti 1.80 S 4 . All of the phases have n-type metallic character and exhibit Pauli paramagnetism, as proven by experiments and first-principles calculations. The Cu and Ti deficiencies in c-Cu 1-x Ti 2 S 4 and r-CuTi 2 S 4 , respectively, decrease the electron-carrier concentration, whereas the {"}excess{"} of Ti ions in c-Cu 1-x Ti 2.25 S 4 largely increases it. For r-CuTi 2 S 4 , the reduced carrier concentration increases the electrical resistivity and Seebeck coefficient, leading to the highest thermoelectric power factor of 0.5 mW K -2 m -1 at 670 K. For all of the Cu-Ti-S phases, the thermal conductivity at 670 K is 3.5-5 W K -1 m -1 , where the lattice part of the conductivity is as low as 1 W K -1 m -1 at 670 K. As a result, r-CuTi 2 S 4 shows the highest dimensionless thermoelectric figure of merit ZT of 0.2. The present systematic study on the Cu-Ti-S systems provides insights into the structural design of thermoelectric materials based on Cu-M-S (M = transition-metal elements).",
author = "Katsuaki Hashikuni and Koichiro Suekuni and Hidetomo Usui and Raju Chetty and Michihiro Ohta and Kazuhiko Kuroki and Toshiro Takabatake and Kosuke Watanabe and Michitaka Ohtaki",
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T1 - Thermoelectric Properties and Electronic Structures of CuTi 2 S 4 Thiospinel and Its Derivatives

T2 - Structural Design for Spinel-Related Thermoelectric Materials

AU - Hashikuni, Katsuaki

AU - Suekuni, Koichiro

AU - Usui, Hidetomo

AU - Chetty, Raju

AU - Ohta, Michihiro

AU - Kuroki, Kazuhiko

AU - Takabatake, Toshiro

AU - Watanabe, Kosuke

AU - Ohtaki, Michitaka

PY - 2019/1/22

Y1 - 2019/1/22

N2 - We report the preparations, thermoelectric and magnetic properties, and electronic structures of Cu-Ti-S systems, namely, cubic thiospinel c-Cu 1-x Ti 2 S 4 (x ≤ 0.375), a derivative cubic and Ti-rich phase c-Cu 1-x Ti 2.25 S 4 (x = 0.5, 0.625), and a rhombohedral phase r-CuTi 2 S 4 . All samples have the target compositions except for r-CuTi 2 S 4 , whose actual composition is Cu 1.14 Ti 1.80 S 4 . All of the phases have n-type metallic character and exhibit Pauli paramagnetism, as proven by experiments and first-principles calculations. The Cu and Ti deficiencies in c-Cu 1-x Ti 2 S 4 and r-CuTi 2 S 4 , respectively, decrease the electron-carrier concentration, whereas the "excess" of Ti ions in c-Cu 1-x Ti 2.25 S 4 largely increases it. For r-CuTi 2 S 4 , the reduced carrier concentration increases the electrical resistivity and Seebeck coefficient, leading to the highest thermoelectric power factor of 0.5 mW K -2 m -1 at 670 K. For all of the Cu-Ti-S phases, the thermal conductivity at 670 K is 3.5-5 W K -1 m -1 , where the lattice part of the conductivity is as low as 1 W K -1 m -1 at 670 K. As a result, r-CuTi 2 S 4 shows the highest dimensionless thermoelectric figure of merit ZT of 0.2. The present systematic study on the Cu-Ti-S systems provides insights into the structural design of thermoelectric materials based on Cu-M-S (M = transition-metal elements).

AB - We report the preparations, thermoelectric and magnetic properties, and electronic structures of Cu-Ti-S systems, namely, cubic thiospinel c-Cu 1-x Ti 2 S 4 (x ≤ 0.375), a derivative cubic and Ti-rich phase c-Cu 1-x Ti 2.25 S 4 (x = 0.5, 0.625), and a rhombohedral phase r-CuTi 2 S 4 . All samples have the target compositions except for r-CuTi 2 S 4 , whose actual composition is Cu 1.14 Ti 1.80 S 4 . All of the phases have n-type metallic character and exhibit Pauli paramagnetism, as proven by experiments and first-principles calculations. The Cu and Ti deficiencies in c-Cu 1-x Ti 2 S 4 and r-CuTi 2 S 4 , respectively, decrease the electron-carrier concentration, whereas the "excess" of Ti ions in c-Cu 1-x Ti 2.25 S 4 largely increases it. For r-CuTi 2 S 4 , the reduced carrier concentration increases the electrical resistivity and Seebeck coefficient, leading to the highest thermoelectric power factor of 0.5 mW K -2 m -1 at 670 K. For all of the Cu-Ti-S phases, the thermal conductivity at 670 K is 3.5-5 W K -1 m -1 , where the lattice part of the conductivity is as low as 1 W K -1 m -1 at 670 K. As a result, r-CuTi 2 S 4 shows the highest dimensionless thermoelectric figure of merit ZT of 0.2. The present systematic study on the Cu-Ti-S systems provides insights into the structural design of thermoelectric materials based on Cu-M-S (M = transition-metal elements).

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U2 - 10.1021/acs.inorgchem.8b02955

DO - 10.1021/acs.inorgchem.8b02955

M3 - Article

VL - 58

SP - 1425

EP - 1432

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 2

ER -