Thermoelectric properties of Sn substituted p-type Nd filled skutterudites

Nd0.6Fe2Co2Sb12−xSnx (0 ⩽ x ⩽ 0.6 nominal) skutterudite compounds were synthesized by traditional heat treatment method. Sn substitution on Sb (24g) site was verified by X-ray powder diffraction, energy dispersive spectrometry, and Raman spectroscopy. It was determined that substituting Sb with Sn increases the Nd filling fraction. Along with the in␣situ nanoinclusions introduced by Sn, the thermoelectric behavior of Sn in Nd0.6Fe2Co2Sb12−xSnx differs from those seen in CoSb3. Despite the increase of electrical resistivity, the enhanced Seebeck coefficient and suppressed lattice thermal conductivity resulted in a 30% improvement of ZT for Nd0.6Fe2Co2Sb11.6Sn0.4 compared with that of Sn-free sample. We hope our work can complement the knowledge of pnicogen-substituted p-type skutterudite family and demonstrate the ways to improve their properties through compositional modification as well as in␣situ formation of nanoinclusions.