Enhanced Thermoelectric and Mechanical Performance in n-Type Yb-Filled Skutterudites through Aluminum Alloying

Dandan Qin; Bo Cui; Jianbo Zhu; Wenjing Shi; Haixu Qin; Fengkai Guo; Jian Cao; Wei Cai; Jiehe Sui

doi:10.1021/acsami.0c01798

Enhanced Thermoelectric and Mechanical Performance in n-Type Yb-Filled Skutterudites through Aluminum Alloying

ACS Appl Mater Interfaces. 2020 Mar 18;12(11):12930-12937. doi: 10.1021/acsami.0c01798. Epub 2020 Mar 5.

Authors

Dandan Qin¹, Bo Cui², Jianbo Zhu¹, Wenjing Shi¹, Haixu Qin¹, Fengkai Guo¹, Jian Cao¹, Wei Cai², Jiehe Sui¹

Affiliations

¹ State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China.
² National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China.

PMID: 32096975
DOI: 10.1021/acsami.0c01798

Abstract

Herein, we demonstrate a synergistic combination of novel mechanisms in aluminum (Al)-alloyed Yb_0.3Co₄Sb₁₂-based thermoelectric materials to address both reduction in thermal conductivity and concomitant enhancement in power factor (PF). Upon Al alloying, CoAl nanoprecipitates are embedded in the matrix, leading to (1) significant local strain and thus intensified phonon scattering and (2) carrier injection because of interphase electron transfer. Moreover, by decreasing the Yb filling fraction, not only is the electronic thermal conductivity significantly suppressed but also the carrier concentration is modulated to the optimum range, thus resulting in the dramatically boosted PF, especially below 773 K. As a result, a peak ZT value of 1.36 at 873 K and ZT_ave of 0.96 from 300 to 873 K were obtained in Yb_0.21Co₄Sb₁₂/0.32CoAl. Last but not the least, the mechanical properties of the Al-alloyed samples were considerably improved through CoAl precipitate hardening, offering great potential for commercial applications.

Keywords: Al alloying; mechanical properties; nanoprecipitates; skutterudites; thermoelectric properties.