Effect of the addition of graphite nanoplatelets on the efficiency of Bi2Te3-based thermoelectric materials by powder metallurgy

Abstract

ABSTRACT : In this research, a comprehensive systematic search was conducted to present an overview, including trends and limitations, in research related to thermoelectric materials. As a result of this analysis, it was found that the aspects related to costs and initiatives associated with circular economy models have been little explored, which represents not only an opportunity for the development of new approaches in the conception of thermoelectric systems, but also for the conception of optimized designs that address the current limitations of this technology. The main objective of this work is to develop a thermoelectric material composed of P-type BiTe base and different percentages by weight of graphite nanoplatelets (0, 0.1%, 0.5 and 1%wt of GNP). This development is complemented by the physicochemical characterization of the raw materials, the ground powders and the formed material, the characterization techniques used were scanning electron microscopy and X-ray diffraction and its thermoelectric properties such as electrical conductivity (S / m), mobility (cm2 ((Vs)), Hall coefficient (cm3 / ° C) and Seebeck coefficient (μV / K). Although the addition of graphite nanoplate did not present a noticeable improvement in the properties thermoelectric, the fabricated materials did present improvements in the properties with respect to thermoelectric evaluated in comparison to those published in the literature. Finally, the characterization of low-cost BiTe base thermoelectric modules typically used for generation (SP1848-27145SA (TEG-GEN)) and cooling (TEC1-12706 (TEC-REF)), both used in this research for heat recovery, was performed. The modules were evaluated against various configurations, distances from the heat source and distributions, to determine the optimal recovery conditions. The experiments were conducted at the laboratory level and in a large-scale kiln of the traditional ceramic industry and revealed that even cooling modules are suitable for energy recovery, particularly in developing countries, where other generators are more expensive and difficult to obtain. These thermoelectric generators were tested for low-temperature heat recovery in regular furnaces to be deployed elsewhere. The results show that even thermoelectric cooling modules can be a solution for heat recovery in many heat sources, particularly strategic for developing countries.