Simultaneous Enhancement of the Thermoelectric and Mechanical Performance in One-Step Sintered n-Type Bi2Te3-Based Alloys via a Facile MgB2 Doping Strategy

Bin Chen; Junqin Li; Mengnan Wu; Lipeng Hu; Fusheng Liu; Weiqin Ao; Yu Li; Heping Xie; Chaohua Zhang

doi:10.1021/acsami.9b16781

Simultaneous Enhancement of the Thermoelectric and Mechanical Performance in One-Step Sintered n-Type Bi₂Te₃-Based Alloys via a Facile MgB₂ Doping Strategy

ACS Appl Mater Interfaces. 2019 Dec 11;11(49):45746-45754. doi: 10.1021/acsami.9b16781. Epub 2019 Dec 2.

Authors

Bin Chen¹, Junqin Li¹, Mengnan Wu¹, Lipeng Hu¹, Fusheng Liu¹, Weiqin Ao¹, Yu Li¹, Heping Xie¹, Chaohua Zhang¹

Affiliation

¹ College of Materials Science and Engineering, Shenzhen Key Laboratory of Special Functional Materials, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Guangdong Research Center for Interfacial Engineering of Functional Materials, Institute of Deep Underground Sciences and Green Energy , Shenzhen University , Shenzhen 518060 , P. R. China.

PMID: 31729854
DOI: 10.1021/acsami.9b16781

Abstract

The Bi₂Te₃-based alloys have been commercialized for the applications of energy harvesting and refrigeration for decades. However, the commercial Bi₂Te₃-based alloys produced by the zone-melting (ZM) method usually show poor mechanical strength and crack problems as well as the sluggish figure of merit ZT, especially for the less-progressed n-type samples. In this work, we have simultaneously enhanced the thermoelectric and mechanical performance of the one-step spark plasma sintering (SPS)-derived n-type Bi₂Te_2.7Se_0.3 alloys just by doping a small amount of superconducting material MgB₂ where Mg and B atoms can play significant roles in carrier density optimization and hardness enhancement. Besides the optimization of carrier density, the MgB₂ doping can also increase the carrier mobility but decrease the lattice and bipolar thermal conductivity, leading to a peak ZT of 0.96 at 325 K and an average ZT of 0.88 within 300-500 K in the 0.5% MgB₂-doped Bi₂Te_2.7Se_0.3 (BTSMB) alloys. The peak ZT and average ZT of our optimized BTSMB samples are comparable and higher than those of the state-of-the-art commercial ZM ingot. Moreover, the optimized BTSMB sample also exhibits almost 70% enhancement in hardness compared with the ZM ingot. Our results demonstrate the great potential of the MgB₂ doping strategy for mass production of SPS-derived Bi₂Te₃-based alloys in one-step sintering.

Keywords: MgB2 doping; bismuth telluride; carrier density optimization; mechanical; thermoelectric.