Thermoelectric properties of In-filled and Te-doped CoSb3 prepared by high-pressure and high-temperature

A novel chemical alloying method of high-pressure and high-temperature (HPHT) has been used for the synthesis of bulk-skutterudite In0.5Co4Sb11.5Te0.5. Through HPHT method, the synthesis time has been shortened from a few days to 30min. The samples of In0.5Co4Sb11.5Te0.5 skutterudites were synthesized at 1.8-3.3GPa. We have studied the phase, the microstructure, and the temperature-dependent thermoelectric properties. The Seebeck coefficient, electrical conductivity and thermal conductivity were measured in the temperature range of 295-673K. As we expected, the thermal conductivity of sample In0.5Co4Sb11.5Te0.5 decreased with the increase of the synthetic pressure. A maximal ZT of 0.64 was achieved for the In0.5Co4Sb11.5Te0.5 synthesized at 1.8GPa at 673K. These results revealed that HPHT method may be helpful for optimizing electrical conductivity and thermal conductivity in a comparatively independent way.