Thermoelectric properties of skutterudite InyCo4−xFexSb12

In-filled and Fe-doped CoSb 3 (In y Co 4− x Fe x Sb 12 ) skutterudites were prepared by encapsulated induction melting and hot pressing, and their thermoelectric and transport properties were examined. A single δ -phase was successfully obtained by subsequent annealing at 823 K for 24 h, but it decomposed to FeSb 2 and Sb when x = 1.5. The Hall and the Seebeck coefficients of the In y Co 4− x Fe x Sb 12 samples had positive signs, indicating p-type conduction by holes. The electrical conductivity was increased by Fe doping, but the thermal conductivity was decreased by In filling due to phonon scattering. The thermoelectric properties were improved by In filling and Fe doping, and were closely related to the optimum carrier concentration and phonon scattering.