Synthesis and consolidation of Ni-Zn substituted tetrahedrite thermoelectric material

Nowadays, the real challenge in the thermoelectric field seems to be the identification of efficient thermoelectric materials which should be inexpensive, easy to synthesize, and comprised of Earth-abundant elements. On this basis, tetrahedrite mineral family (Cu12-xTrxSb4S13 where Tr= Mn, Fe, Co, Ni, Zn), one of the most widespread sulfosalts on Earth's crust, seems to meet the right features for an attractive p-Type Pb-free thermoelectric material, showing a relatively high conversion efficiency [1-2]. Both solid state reaction and solvothermal synthesis approaches were employed for a fast and easy way for Ni-Zn substituted tetrahedrite development. Reactive open die pressing was employed for consolidation of the material [3]. The influence of the stoichiometry, the synthesis conditions and the reactive consolidation process parameters on the tetrahedrite phase content and density of the samples were investigated by X-ray diffraction (with a profile Rietveld refinements) and scanning electron microscope (equipped with energy dispersive X-ray spectroscopy). The thermoelectric properties of the samples (electrical conductivity and Seebeck coefficient measurements, and laser flash analysis) were also performed. Furthermore, the thermal stability of the material was investigated by thermal analyses. References: [1] X. Lu, D.T. Morelli, Physical Chemistry Chemical Physics, 15 (2013) 5762-5766. [2] [1] X. Lu, D.T. Morelli, Y. Xia, V. Ozolins, Chemistry of Materials, 27 (2015) 408-413.. [3] Ceresara, S., C. Fanciulli, F. Passaretti, D. Vasilevskiy. Journal of Electronic Materials 42(7) (2013) 1529-1534.