HPHT synthesis and enhanced thermoelectric transport properties of double-doped Co4Sb11TexSn1-x skutterudites

The high-pressure and high-temperature (HPHT) technique was employed to prepare skutterudite-based polycrystalline materials Co4Sb11TexSn1-x (x = 0.5, 0.6, 0.7). The thermoelectric properties, as well as electrical transport properties near room temperature, were researched systematically. The results indicated that the Sn and Te co-doped specimens yielded an impressive depression in lattice thermal conductivity (kappa(L)) based on the point-defect scattering. The kappa(L) exhibited a positive Te doping level dependence. Therefore, a minimum lattice thermal conductivity was 1.41 Wm(-1)K(-1) for Co4Sb11Te0.7Sn0.3. Consequently, the thermoelectric dimensionless figure of merit, ZT, was remarkably enhanced from 300 to 725 K. The maximum ZT was 1.13 for Co4Sb11Te0.7Sn0.3 at 711 K, which is better than that of pure Co4Sb12. This value is nearly improved one order of magnitude and rivals the state-of-the-art single-filled n-type skutterudite compounds. Compared to the traditional synthesized method, high pressure and high-temperature techniques can fundamentally reduce the reaction duration from several days to less than an hour and provide a different route for the synthesis of thermoelectric materials. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The HPHT technique was used to prepare Co4Sb11TexSn1-x materials, which exhibited improved thermoelectric performance with a minimum lattice thermal conductivity of 1.41 Wm(-1)K(-1) and a maximum ZT of 1.13. This method significantly reduced reaction duration and offers a novel route for the synthesis of thermoelectric materials.