Thermoelectric Properties of n-Type Multiple-Filled Skutterudites

Filled skutterudites are prospective intermediate temperature materials fora thermoelectric pound power generation. CoSb3-based n-type filled skutterudites have good electrical transport properties with power factor values over 40 mu W/cm K-2 at elevated temperatures. Filling multiple fillers into the crystallographic voids of skutterudites would help scatter a broad range of lattice phonons, thus resulting in lower lattice thermal conductivity values. We report the thermoelectric properties of n-type multiple-filled skutterudites between 5 K and 800 K. The combination of different fillers inside the voids of the skutterudite structure shows enhanced phonon scattering, and consequently a strong suppression of the lattice thermal conductivity. Very good power factor values are achieved in multiple-filled skutterudite compared with single-element-filled materials. The dimensionless thermoelectric figure of merit for n-type filled skutterudites is improved through multiple-filling in a wide temperature range.