Preparation and thermoelectric performance of tetrahedrite-like cubic Cu₃SbS₃ compound

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.