Regular Article

Effect of evolution for dispersed phase on thermoelectric performance of Yb_0.2(CoSb_2.875Te_0.125)₄^★

College of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, P.R. China

^* e-mail: liuhq@sdust.edu.cn; qingkunhe@163.com; tobyzhang1992@163.com

Received: 14 October 2021
Received in final form: 26 December 2021
Accepted: 14 January 2022
Published online: 4 February 2022

Abstract

CoSb₃-based skutterudites, as a medium-temperature thermoelectric material, show excellent thermoelectric performance, but high thermal conductivity suppresses the high ZT value. Here, x% SnTe/Yb_0.2(CoSb_2.875Te_0.125)₄ samples were synthesized through vacuum melting reaction and spark plasma sintering (SPS). With increasing of SnTe content, the dispersed phase CoSb₂, SnTe and CoTe₂ appear successively via a selection of nucleation kinetics for 1%, 3% and 5% SnTe composited sample. Due to scattering of the dispersed phase and the solid solution distortion, lattice conductivity (κ_lat) of the 3% SnTe/Yb_0.2(CoSb_2.875Te_0.125)₄ sample decreases from 1.55 W m⁻¹ K⁻¹ to 1.19 W m⁻¹ K⁻¹ compared with the Yb_0.2(CoSb_2.875Te_0.125)₄ sample, which reduces by ∼22.8% at 773 K. The maximum thermoelectric merit ZT of the 3% SnTe/Yb_0.2(CoSb_2.875Te_0.125)₄ sample achieves 1.18 at 773 K.