Enhanced thermoelectric properties of n-type filled skutterudite Yb0.35Co4Sb12 by substitution on both the Co and Sb sites

A dimensionless thermoelectric figure of merit (ZT) of about 1.2 was reported in Yb0.35Co4Sb12 at 550$^{\circ}$C by ball milling and hot pressing. Through alloying on both the Co and Sb sites, we expect to achieve lower thermal conductivity while maintaining the power factor. The composition tuning is aimed for reducing the electrical conductivity and increasing the Seebeck coefficient, which will lead to a lower thermal conductivity, and ultimately higher ZT. In this report, we present the thermoelectric properties of skutterudites Yb0.35FexCo4-2xNixSb12 and Yb0.35Co4Sb12-yMy (M=Si, Ge, Sn, B, Al, Ga, In, etc.).