Melt-centrifuged (Bi,Sb) 2 Te 3: Engineering microstructure toward high thermoelectric efficiency

Yu Pan, Umut Aydemir, Jann A. Grovogui, Ian T. Witting, Riley Hanus, Yaobin Xu, Jinsong Wu, Chao Feng Wu, Fu Hua Sun, Hua Lu Zhuang, Jin Feng Dong, Jing Feng Li, Vinayak P. Dravid, G. Jeffrey Snyder

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

Microstructure engineering is an effective strategy to reduce lattice thermal conductivity (κ l ) and enhance the thermoelectric figure of merit (zT). Through a new process based on melt-centrifugation to squeeze out excess eutectic liquid, microstructure modulation is realized to manipulate the formation of dislocations and clean grain boundaries, resulting in a porous network with a platelet structure. In this way, phonon transport is strongly disrupted by a combination of porosity, pore surfaces/junctions, grain boundaries, and lattice dislocations. These collectively result in a ≈60% reduction of κ l compared to zone melted ingot, while the charge carriers remain relatively mobile across the liquid-fused grains. This porous material displays a zT value of 1.2, which is higher than fully dense conventional zone melted ingots and hot pressed (Bi,Sb) 2 Te 3 alloys. A segmented leg of melt-centrifuged Bi 0.5 Sb 1.5 Te 3 and Bi 0.3 Sb 1.7 Te 3 could produce a high device ZT exceeding 1.0 over the whole temperature range of 323–523 K and an efficiency up to 9%. The present work demonstrates a method for synthesizing high-efficiency porous thermoelectric materials through an unconventional melt-centrifugation technique.

Original languageEnglish (US)
Article number1802016
JournalAdvanced Materials
Volume30
Issue number34
DOIs
StatePublished - Jan 1 2018

Keywords

  • Dislocation
  • Liquid phase sintering
  • Melt-centrifugation
  • P-type bismuth-antimony-telluride
  • Thermoelectric

ASJC Scopus subject areas

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

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