A Review of the Mg2(Si,Sn) Alloy System as Emerging Thermoelectric Material: Experimental and Modeling Aspects

Abstract

This paper reviews the basic understanding of Mg-based thermoelectric materials and various approaches for increasing their thermoelectric efficiency. Recent developments in terms of enhancement of electrical properties and reduction of thermal conductivity of Mg2(Si,Sn) materials through experimental investigation and applying modeling approaches are discussed in detail. Further, the role of deformation and heat treatment analysis for achieving optimum thermoelectric properties in this material system and its prospects for further developments as a commercially viable solution is enumerated. The solid solutions of Mg2X (X = Si,Ge,Sn) thermoelectric material are identified as the most favorable alloy class of thermoelectric materials for application in the intermediate temperature range (400–800 K). The reason for Mg2X alloys becoming the preferred choice over others is because they are cheap, abundant and non-toxic. Improving the efficiency of magnesium-based thermoelectric materials through various advancements in experimental methods has appeared as a matter of great commercial importance. However, theoretical understanding of the phenomenological issues confronting the attainment of desirably high thermoelectric properties has not been widely touched upon; this leads to enormous opportunities for optimizing the figure of merit of thermoelectric materials through numerical modeling and simulation techniques. Also, deforming the alloys has been proved to be favorable for the thermoelectric performance of the material; a lot of work has been carried out for other classes of thermoelectric materials, but there is a disparity in interpreting the deformation behavior of Mg2Si1−xSnx alloys and its impact on thermoelectric properties due to lack of adequate efforts to conduct systematic investigations in the area of concern.