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Title: Multiple-Filled Skutterudites: High Thermoelectric Figure of Merit through Separately Optimizing Electrical and Thermal Transports

Abstract

Skutterudites CoSb{sub 3} with multiple cofillers Ba, La, and Yb were synthesized and very high thermoelectric figure of merit ZT = 1.7 at 850 K was realized. X-ray diffraction of the densified multiple-filled bulk samples reveals all samples are phase pure. High-resolution scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDS) analysis confirm that multiple guest fillers occupy the nanoscale-cages in the skutterudites. The fillers are further shown to be uniformly distributed and the Co-Sb skutterudite framework is virtually unperturbed from atomic scale to a few micrometers. Our results firmly show that high power factors can be realized by adjusting the total filling fraction of fillers with different charge states to reach the optimum carrier density, at the same time, lattice thermal conductivity can also be significantly reduced, to values near the glass limit of these materials, through combining filler species of different rattling frequencies to achieve broad-frequency phonon scattering. Therefore, partially filled skutterudites with multiple fillers of different chemical nature render unique structural characteristics for optimizing electrical and thermal transports in a relatively independent way, leading to continually enhanced ZT values from single- to double-, and finally to multiple-filled skutterudites. The idea of combining multiple fillers withmore » different charge states and rattling frequencies for performance optimization is also expected to be valid for other caged TE compounds.« less

Authors:
 [1];  [1];  [2];  [3];  [4];  [5];  [3];  [4];  [1];  [1]
  1. Chinese Academy of Sciences
  2. General Motors Corporation
  3. ORNL
  4. GM R&D and Planning, Warren, Michigan
  5. General Motors Corporation-R&D
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); High Temperature Materials Laboratory; Shared Research Equipment Collaborative Research Center
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1024684
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 133; Journal Issue: 20; Journal ID: ISSN 0002-7863
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CARRIER DENSITY; CHARGE STATES; FILLERS; GLASS; OPTIMIZATION; PERFORMANCE; PHONONS; POWER FACTOR; SCATTERING; THERMAL CONDUCTIVITY; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION; X-RAY SPECTROSCOPY

Citation Formats

Zhang, Weiqing, Yang, Jiong, Yang, Jihui, Wang, Hsin, Salvador, James R., Shi, Xun, Chi, Miaofang, Cho, Jung Y, Bai, Shengqiang, and Chen, Lidong. Multiple-Filled Skutterudites: High Thermoelectric Figure of Merit through Separately Optimizing Electrical and Thermal Transports. United States: N. p., 2011. Web.
Zhang, Weiqing, Yang, Jiong, Yang, Jihui, Wang, Hsin, Salvador, James R., Shi, Xun, Chi, Miaofang, Cho, Jung Y, Bai, Shengqiang, & Chen, Lidong. Multiple-Filled Skutterudites: High Thermoelectric Figure of Merit through Separately Optimizing Electrical and Thermal Transports. United States.
Zhang, Weiqing, Yang, Jiong, Yang, Jihui, Wang, Hsin, Salvador, James R., Shi, Xun, Chi, Miaofang, Cho, Jung Y, Bai, Shengqiang, and Chen, Lidong. Sat . "Multiple-Filled Skutterudites: High Thermoelectric Figure of Merit through Separately Optimizing Electrical and Thermal Transports". United States.
@article{osti_1024684,
title = {Multiple-Filled Skutterudites: High Thermoelectric Figure of Merit through Separately Optimizing Electrical and Thermal Transports},
author = {Zhang, Weiqing and Yang, Jiong and Yang, Jihui and Wang, Hsin and Salvador, James R. and Shi, Xun and Chi, Miaofang and Cho, Jung Y and Bai, Shengqiang and Chen, Lidong},
abstractNote = {Skutterudites CoSb{sub 3} with multiple cofillers Ba, La, and Yb were synthesized and very high thermoelectric figure of merit ZT = 1.7 at 850 K was realized. X-ray diffraction of the densified multiple-filled bulk samples reveals all samples are phase pure. High-resolution scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDS) analysis confirm that multiple guest fillers occupy the nanoscale-cages in the skutterudites. The fillers are further shown to be uniformly distributed and the Co-Sb skutterudite framework is virtually unperturbed from atomic scale to a few micrometers. Our results firmly show that high power factors can be realized by adjusting the total filling fraction of fillers with different charge states to reach the optimum carrier density, at the same time, lattice thermal conductivity can also be significantly reduced, to values near the glass limit of these materials, through combining filler species of different rattling frequencies to achieve broad-frequency phonon scattering. Therefore, partially filled skutterudites with multiple fillers of different chemical nature render unique structural characteristics for optimizing electrical and thermal transports in a relatively independent way, leading to continually enhanced ZT values from single- to double-, and finally to multiple-filled skutterudites. The idea of combining multiple fillers with different charge states and rattling frequencies for performance optimization is also expected to be valid for other caged TE compounds.},
doi = {},
journal = {Journal of the American Chemical Society},
issn = {0002-7863},
number = 20,
volume = 133,
place = {United States},
year = {2011},
month = {1}
}