Low thermal conductivity and high thermoelectric figure of merit in n-type BaxYbyCo4Sb12 double-filled skutterudites

Abstract

Filled skutterudites are one of the most promising thermoelectric materials for power generation applications. The choice and concentration of filler atoms are key aspects for achieving high thermoelectric figure of merit values. We report on the high temperature thermoelectric properties in the double-filled skutterudites ${\mathrm{Ba}}_x{\mathrm{Yb}}_y{\mathrm{Co}}_4{\mathrm{Sb}}_{12}$ . The combination of Ba and Yb fillers inside the voids of the skutterudite structure provides a broad range of resonant phonon scattering and consequently a strong suppression in the lattice thermal conductivity is observed. A dimensionless thermoelectric figure of merit of 1.36 at $800\mathrm{K}$ is achievable for $n$ -type ${\mathrm{Ba}}_x{\mathrm{Yb}}_y{\mathrm{Co}}_4{\mathrm{Sb}}_{12}$ .