Preparation and thermoelectric performance of tetrahedrite-like cubic Cu3SbS3 compound

Abstract

Thermoelectric (TE) Cu3SbS3, as one of the Cu–Sb–S families, has the characteristic of strong anharmonicity of lattice vibrations. It may be a potential replacement for the unstable pristine tetrahedrite, provided that its cubic structure can be stabilised. In this study, pristine (near)-phase-pure cubic Cu3SbS3 and Fe-doped samples were successfully prepared by sequential use of equilibrium and non-equilibrium synthesis techniques. TE properties of both pristine and doped samples were optimised by tuning the sintering parameters. A maximum zT of 0.57 was achieved at 350 °C in pristine (near)-phase-pure cubic Cu3SbS3 sample hot pressed at 575 °C for 30 min, which is about 2.7 times higher than that of the spark plasma sintered one. The Fe-doped sample sintered at 575 °C for 45 min displays a higher zT in the whole testing temperature range and a maximum of 0.62 was reached at 350 °C. The influences of hot pressing and spark plasma sintering on the phase structure, microstructure, thermodynamic and TE properties were studied and correlated. The results demonstrated the potential of cubic Cu3SbS3 as a high-performance material.