Thermoelectric Materials

Thermoelectric (TE) materials have unique property of converting waste heat into useful electrical energy and vice versa, thus utilizing two material property effects that have been studied since 1800ís: Seebeck effect and Peltier effect. Current TE materials have low conversion efficiencies at higher temperatures and uses expensive elemental materials (Te, Ge, etc.), which contribute to their present limited application.

Our laboratory research focuses on the development of new TE materials for high-temperature applications. Currently, the TE materials under investigation include binary and ternary alloys of metal borides and silicides. These TE materials have great potential to exhibit higher figure of merit (ZT) at higher temperatures.

The TE Materials are produced using synthetic methods such as cold pressing, sintering, and arc melting. All experimental parameters are optimized during the production of TE materials. The product samples are characterized with SEM, TEM, EDAX, and X-ray diffraction techniques. The structure, phase stability, and purity of the TE materials are determined using these techniques.

Transport properties (Seebeck coefficient, electrical conductivity and thermal conductivity) of the TE materials are experimentally determined and figure of merit (ZT) is calculated at higher temperatures (400 - 1200 oC). Thermodynamic properties (Specific heat, change in enthalpy, entropy Gibbs energy, and activities)
are calculated  for the TE alloys at these temperatures.

Thermodynamic modeling and Phase diagrams of the TE materials is carried out using computational tools. Database of transport properties, thermodynamic properties, and phase equilibria of high ZT TE materials is developed for high temperature applications like aluminum, steel and automobile industries.