Thermoelectric properties of YbxCo4Sb12 system

YbxCo4Sb12 polycrystals were fabricated by vacuum melting combined with hot-press sintering. The effect of Yb-filling on thermoelectric property of unfilled skutterudite CoSb3 was investigated, which indicated the enhancement of the power factor of the material. Transport properties of materials changed from semi-conductor to semi-metal during the measurement of electrical conductivity, which indicated the change of electronic band structure. The maximum value of electrical conductivity was about 190000 S/m at 300 K for all samples. On the basis of Yb-filling, power factor of Yb0.2Co4Sb12 reached 5–6 mW/(mK) during the measurement temperature. Thermal conductivity decreased with increase of Yb content, and the thermal conductivity of Yb0.2Co4Sb12 reached 3.2 W/(mK) at 600 K. The ZT value of Yb0.2Co4Sb12 reached 1.16 at 700 K due to positive contribution from high power factor and low thermal conductivity.