Transport properties of Cu_xCo₄Sb_11.7Te_0.3 prepared by solid-state reaction

Abstract

The Skutterudite compounds have been extensively studied worldwide over the past several years for their potential advanced thermoelectric applications in the intermediate temperature range. However, most methods for synthesis of CoSb₃ materials require a long-duration heating process and complex equipments. In this study, a simple solid-state reaction method was used to prepare copper-tellurium co-doped CoSb₃ ( Cu_xCo₄Sb_11.7Te_0.3, x = 0-0.4) bulk thermoelectric materials. The obtained samples show enhanced thermoelectric properties compared to Cu-undoped sample. Especially in the case of Cu-doped CoSb₃, the compound Cu_0.4Co₄Sb_11.7Te_0.3 exhibits a maximal Seebeck coefficient of 234.2 µVK^− 1 at 617 K, the sample Cu_0.1Co₄Sb_11.7Te_0.3 reaches a power factor of 2012.35 mWm^− 1 K^− 2 at 715.7 K. Moreover, phonon scattering appears to be enhanced due to the significant reduction in grain size of the samples prepared by the solid-state reaction method, resulting in a minimum thermal conductivity of 1.67 Wm^− 1 K^− 1. A dimensionless figure of merit (ZT) of 0.68 was obtained for Cu_0.3Co₄Sb_11.7Te_0.3 at 716 K. Thus, the solid-state reaction method is a feasible strategy for the preparation of Skutterudite thermoelectric materials.