Synthesis and thermoelectric properties of Nd-single filled p-type skutterudites

We report the synthesis of Nd-filled and Fe substituted p-type Nd_xFe_3.2Co_0.8Sb₁₂ (x=0.5, 0.6, 0.7, 0.8, and 0.9) skutterudites by the solid-state reaction method. The influences of Nd filler on the electrical and thermal transport properties are investigated in a temperature range from room temperature to 850 K. A lowest lattice thermal conductivity of 0.88 W·m^-1·K^-1 is obtained in Nd_0.8Fe_3.2Co_0.8Sb₁₂ at 673 K, which results from the localized vibration modes of fillers and the increase of grains boundaries. Meanwhile, the maximum power factor is 2.77 mW·m^-1·K^-2 for the Nd_0.9Fe_3.2Co_0.8Sb₁₂ sample at 668 K. Overall, the highest dimensionless figure of merit zT=0.87 is achieved at 714 K for Nd_0.9Fe_3.2Co_0.8Sb₁₂.