Iterative design of a high zT thermoelectric material

Abstract

Designing a high efficiency thermoelectric material for thermal to electric energy conversion means simultaneously optimizing multiple properties of the material. Although it might seem straightforward to maximize the electrical power and minimize thermal losses, the convoluted relationship between these properties makes optimization complex, requiring a more sophisticated algorithm. The Accelerated Insertion of Materials (AIM) methodology developed to engineer the mechanical properties of complex multiphase steel alloys provides a framework for optimization that can be applied to engineer the thermal and electrical transport properties of a multiphase thermoelectric material. The AIM methodology can be utilized in creating a high figure of merit (zT) material by considering the effects of each structural parameter, such as grain size and grain boundary properties, precipitate volume fraction, and doping and defect concentration of the matrix phase on the zT of the material using a variety of analytical models. The combination of these models provides a way to accelerate the design of high zT materials.

Shapes of phases in isothermal phase diagrams: what is wrong with the Thermo-Calc logo

“…For example, equilibrium phase diagrams can be used to predict the processing required to design high-performance metal alloys 21,22 and even multi-phase thermoelectric alloys. 23 Often these efforts start with exploring the phase space of the elements using the CALculation of PHase Dagrams 24 (CALPHAD) method with software such as Thermo-Calc 25 The shape of the single-phase region in a phase diagram gives essential information on the extent and solubility of defects at various temperatures and chemical conditions. In an A-B binary eutectic system, for example, the equilibrium solubility of B in A is determined by the concentration of point defects present in a two-phase sample, which changes with temperature (Fig.…”

“…For example, equilibrium phase diagrams can be used to predict the processing required to design high-performance metal alloys 21,22 and even multi-phase thermoelectric alloys. 23 Often these efforts start with exploring the phase space of the elements using the CALculation of PHase Dagrams 24 (CALPHAD) method with software such as Thermo-Calc 25…”