Simultaneous Optimization of Power Factor and Thermal Conductivity towards High-Performance InSb-Based Thermoelectric MaterialsSupported by the National Natural Science Foundation of China (Grant Nos. 52002137, 51772109, 51872102, and 51802070), the Fundamental Research Funds for the Central Universities (Grant Nos. 2021XXJS008 and 2018KFYXKJC002), and Graduates’ Innovation Fund of Huazhong University of Science and Technology (Grant No. 2020yjsCXCY022).

Abstract

Thermoelectric performance of InSb is restricted by its low Seebeck coefficient and high thermal conductivity. Here, CuCl is employed to optimize simultaneously the electrical and thermal transport properties of InSb. The substitution of Cl for Sb results in enhanced electron effective mass, leading to high Seebeck coefficient of –159.9 μV/K and high power factor of 31.5 μW⋅cm−1⋅K−2 at 733 K for InSb + 5 wt% CuCl sample. In addition, CuCl doping creates hierarchical architectures composed of Cu9In4, Sb, Cu2Sb in InSb, leading to a strengthened phonon scattering in a wide wavelength (i.e., nano to meso scale), thus a low lattice thermal conductivity of 2.97 W⋅m−1⋅K−1 at 733 K in InSb + 5 wt% CuCl. As a result, a maximum ZT of 0.77 at 733 K has been achieved for the InSb + 5 wt% CuCl sample, increasing by ∼ 250% compared to pristine InSb.