Scalable route for Ni and Zn doped tetrahedrite pellets

Tetrahedrite mineral family, one of the most widespread sulfosalts on Earth's crust, seems to meet the right features for an attractive sustainable p-Type Pb-free thermoelectric material, showing relatively high conversion efficiency, achieving a figure of merit value of almost 1 at 450°C [1,2]. In this work, Ni-Zn co-doped tetrahedrite samples were prepared by Open Die Pressing one step reactive consolidation method [3], employing previously ball milled sulphide powder precursors, in order to identify a simple cheap scalable fast production route for thermoelectric pellets. The influence of dopant presence and reactive consolidation process parameters on the tetrahedrite phase content, stoichiometry and density of the samples were investigated by X-ray diffraction, scanning electron microscope (equipped with energy dispersive Xray spectroscopy), and thermogravimetric analysis. Laser Flash Analysis, electrical conductivity, and Seebeck coefficient measurements were carried out for obtaining a complete thermoelectric characterization.