Filled skutterudites: from single to multiple filling

Abstract

Research on traditional thermoelectric (TE) materials with narrow bandgap have made great progress in recent years. Here, we primarily reviewed the study on CoSb3 skuttuerdites with intrinsic crystal voids that could be partially filled with various filler atoms for TE performance optimization. By combining experimental measurement of electrical/thermal transport properties and theoretical study of electronic structure and structural stability, we analyzed the fundamentals in understanding the filling behavior of fillers atoms in the voids, and provided a few guidance rules in simultaneously optimizing electrical and thermal transport properties for thermoelectric performance optimization. By following those rules, nearly independent tunning of electron and phonon transports can be achieved in these caged compounds. As a result, these partially filled skutterudites basically satisfy the picture of the ‘phonon glass-electron crystal’ paradigm, and TE figure of merit ( ZT ) was pushed up to reach 1.7@850 K, highest among all reported bulk TE materials. The general discussions could also provide guidance in searching for novel thermoelectric materials.