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Title: High-efficiency thermoelectric Ba 8Cu 14Ge 6P 26: bridging the gap between tetrel-based and tetrel-free clathrates

Abstract

A new type-I clathrate, Ba 8Cu 14Ge 6P 26, was synthesized by solid-state methods as a polycrystalline powder and grown as a cm-sized single crystal via the vertical Bridgman method. Single-crystal and powder X-ray diffraction show that Ba 8Cu 14Ge 6P 26 crystallizes in the cubic space group Pm$$\bar{3}$$n (no. 223). Ba 8Cu 14Ge 6P 26 is the first representative of anionic clathrates whose framework is composed of three atom types of very different chemical natures: a transition metal, tetrel element, and pnicogen. Uniform distribution of the Cu, Ge, and P atoms over the framework sites and the absence of any superstructural or local ordering in Ba 8Cu 4Ge 6P 26 were confirmed by synchrotron X-ray diffraction, electron diffraction and high-angle annular dark field scanning transmission electron microscopy, and neutron and X-ray pair distribution function analyses. Characterization of the transport properties demonstrate that Ba 8Cu 14Ge 6P 26 is a p-type semiconductor with an intrinsically low thermal conductivity of 0.72 W m -1K -1 at 812 K. The thermoelectric figure of merit, ZT, for a slice of the Bridgman-grown crystal of Ba 8Cu 14Ge 6P 26 approaches 0.63 at 812 K due to a high power factor of 5.62 μW cm -1 K -2. The thermoelectric efficiency of Ba 8Cu 14Ge 6P 26 is on par with the best optimized p-type Ge-based clathrates and outperforms the majority of clathrates in the 700–850 K temperature region, including all tetrel-free clathrates. Ba 8Cu 14Ge 6P 26 expands clathrate chemistry by bridging conventional tetrel-based and tetrel-free clathrates. Advanced transport properties, in combination with earth-abundant framework elements and congruent melting make Ba 8Cu 14Ge 6P 26 a strong candidate as a novel and efficient thermoelectric material.

Authors:
ORCiD logo [1];  [2];  [3];  [4];  [4];  [5]; ORCiD logo [6]
  1. Iowa State Univ., Ames, IA (United States); Univ. of California, Davis, CA (United States)
  2. National Center for Scientific Research (CNRS), Caen (France)
  3. Univ. of California, Davis, CA (United States); Jet Propulsion Lab., Pasadena, CA (United States)
  4. Univ. of California, Davis, CA (United States)
  5. Jet Propulsion Lab., Pasadena, CA (United States)
  6. Iowa State Univ., Ames, IA (United States); Univ. of California, Davis, CA (United States); Ames Lab., Ames, IA (United States)
Publication Date:
Research Org.:
Univ. of California, Davis, CA (United States); Univ., of Chicago, Chicago, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1409482
Alternate Identifier(s):
OSTI ID: 1506077
Grant/Contract Number:  
SC0008931; AC02-06CH11357
Resource Type:
Published Article
Journal Name:
Chemical Science
Additional Journal Information:
Journal Volume: 8; Journal Issue: 12; Journal ID: ISSN 2041-6520
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE

Citation Formats

Wang, Jian, Lebedev, Oleg I., Lee, Kathleen, Dolyniuk, Juli-Anna, Klavins, Peter, Bux, Sabah, and Kovnir, Kirill. High-efficiency thermoelectric Ba8Cu14Ge6P26: bridging the gap between tetrel-based and tetrel-free clathrates. United States: N. p., 2017. Web. doi:10.1039/c7sc03482b.
Wang, Jian, Lebedev, Oleg I., Lee, Kathleen, Dolyniuk, Juli-Anna, Klavins, Peter, Bux, Sabah, & Kovnir, Kirill. High-efficiency thermoelectric Ba8Cu14Ge6P26: bridging the gap between tetrel-based and tetrel-free clathrates. United States. doi:10.1039/c7sc03482b.
Wang, Jian, Lebedev, Oleg I., Lee, Kathleen, Dolyniuk, Juli-Anna, Klavins, Peter, Bux, Sabah, and Kovnir, Kirill. Fri . "High-efficiency thermoelectric Ba8Cu14Ge6P26: bridging the gap between tetrel-based and tetrel-free clathrates". United States. doi:10.1039/c7sc03482b.
@article{osti_1409482,
title = {High-efficiency thermoelectric Ba8Cu14Ge6P26: bridging the gap between tetrel-based and tetrel-free clathrates},
author = {Wang, Jian and Lebedev, Oleg I. and Lee, Kathleen and Dolyniuk, Juli-Anna and Klavins, Peter and Bux, Sabah and Kovnir, Kirill},
abstractNote = {A new type-I clathrate, Ba8Cu14Ge6P26, was synthesized by solid-state methods as a polycrystalline powder and grown as a cm-sized single crystal via the vertical Bridgman method. Single-crystal and powder X-ray diffraction show that Ba8Cu14Ge6P26 crystallizes in the cubic space group Pm$\bar{3}$n (no. 223). Ba8Cu14Ge6P26 is the first representative of anionic clathrates whose framework is composed of three atom types of very different chemical natures: a transition metal, tetrel element, and pnicogen. Uniform distribution of the Cu, Ge, and P atoms over the framework sites and the absence of any superstructural or local ordering in Ba8Cu4Ge6P26 were confirmed by synchrotron X-ray diffraction, electron diffraction and high-angle annular dark field scanning transmission electron microscopy, and neutron and X-ray pair distribution function analyses. Characterization of the transport properties demonstrate that Ba8Cu14Ge6P26 is a p-type semiconductor with an intrinsically low thermal conductivity of 0.72 W m-1K-1 at 812 K. The thermoelectric figure of merit, ZT, for a slice of the Bridgman-grown crystal of Ba8Cu14Ge6P26 approaches 0.63 at 812 K due to a high power factor of 5.62 μW cm-1 K-2. The thermoelectric efficiency of Ba8Cu14Ge6P26 is on par with the best optimized p-type Ge-based clathrates and outperforms the majority of clathrates in the 700–850 K temperature region, including all tetrel-free clathrates. Ba8Cu14Ge6P26 expands clathrate chemistry by bridging conventional tetrel-based and tetrel-free clathrates. Advanced transport properties, in combination with earth-abundant framework elements and congruent melting make Ba8Cu14Ge6P26 a strong candidate as a novel and efficient thermoelectric material.},
doi = {10.1039/c7sc03482b},
journal = {Chemical Science},
number = 12,
volume = 8,
place = {United States},
year = {2017},
month = {9}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1039/c7sc03482b

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Cited by: 12 works
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