Enhancement of thermoelectric properties of electropositive and electronegative element double-filled CoSb3 via high-pressure regulating

Abstract

In this paper, the electropositive-electronegative double-filled skutterudite, which is challenging or impossible to synthesize via conventional methods, was successfully prepared using a high-pressure and high-temperature (HPHT) method. The successful filling of Ba-S into the voids of the CoSb₃ crystal structure was confirmed through X-ray diffraction, enthalpy of formation calculations, and EDS spectral analysis. The experimental results indicate that the skutterudite material with porous structure has a lower thermal conductivity of 1.07 W m⁻¹ K⁻¹ at 773 K. The Callaway model fitting analysis revealed that the introduction of Ba, S, and Te enhances both point defect scattering and resonance scattering, thereby effectively reducing the lattice thermal conductivity Consequently, the sample achieves a maximum zT value of 1.44 at 773 K. This work provides novel insights into the study of thermoelectric properties in skutterudite materials.