Thermoelectric properties of uranium filled skutterudites U (Fe Co4−)Sb12

Abstract The filled skutterudites of the form U y Fe x Co 4− x Sb 12 were fabricated and the thermoelectric properties for certain samples studied. For samples containing 100% cobalt, uranium could not be incorporated, or ‘filled’, into the voids in the skutterudite structure. With substitution of iron for cobalt the void occupancy by uranium increased. Uranium filled samples indicated relatively large Seebeck coefficient and p-type behavior. The thermal conductivity, especially below 500 K, of U y Fe x Co 4− x Sb 12 was strongly depressed by uranium filling and iron substitution. The dimensionless thermoelectric figure of merits, ZT , were improved by uranium filling and showed a maximum value ZT = 0.55 at 800 K for U 0.2 FeCo 3 Sb 12 of nominal composition.