Resnick Institute

Thermoelectrics

diagram

Phase Equilibria and Microstructural Studies of Thermoelectrically Important Co-Sb-Ga System

The project's aim is to provide leadership in the burgeoning field of self-assembled, composite thermoelectrics by establishing an expertise in composite skutterudites.

In this project, Caltech will develop new high thermoelectric efficiency skutterudite composites capitalizing on the unique strengths and capabilities of Prof. Sinn-wen Chen's group at NTHU, Taiwan.

The research objectives at Caltech will be to identify high efficiency (ZT) skutterudite composites.

In year 1 ternary Co-Sb-M composites will be made using precipitation reactions and directionally solidified Bridgeman samples, starting with M=Ga and proceeding to other candidates such as In, Ni, Fe, Ce.

In year 2 Caltech will design thermoelectric nanocomposites using the initial phase diagram information of NTHU and use this information to control the characteristic size and morphology of the microstructure. The addition of doping elements to control carrier concentration will be included to assess the influence of microstructure on doping control.

In year 3 synthesis procedures (composition, time and temperature of growth and annealing) will be developed based on the phase diagrams to create microstructures of properly doped skutterudites with phonon-scattering secondary phases resulting in high thermoelectric efficiency.