Solid-state preparation and electrical properties of the marcasite type compound FeTe2-xBix

Abstract

Thermoelectric material is a new type of energy conversion material that can use temperature differences to generate electricity, and the research on thermoelectric material has important significance in the energy crisis today. In this paper, the compounds FeTe2-xBix (x=0.05, 0.1, 0.3, 0.5, 0.7) were prepared by the solid-state reaction method, the preparation conditions with the temperature interval of 653~863 K, and the holding time within 30 min. The physical structure and microstructure of FeTe2-xBix were determined by XRD and SEM. The results show that the main substances synthesized by solid-state reaction for FeTe2-xBix are Bi2Te3 and FeTe2, and the sample crystals were found to have a lamellar structure by SEM testing. With the increase of Bi doping coefficient, the power factor shows an increasing trend. The power factor of the components with large doping coefficients decreased with the increase of the synthesis temperature, while the power factor of the components with low doping coefficients did not change significantly. When the preparation temperature was 653 K, the sample FeTe1.3Bi0.7 obtained the highest absolute Seebeck coefficient ∼145 μV/K at room temperature, when the preparation temperature was 833 K, the sample FeTe1.5Bi0.5 obtained the lowest resistivity of about 1.4 mΩ·cm at room temperature, and when the preparation temperature was 693 K the sample FeTe1.5Bi0.5 obtained a maximum power factor of about 417.88 μW·m−1K−2.