Fabrication and Thermoelectric Power Factor of CoSb3 Prepared using Modified Polyol Process and Evacuated- and-Encapsulated Sintering

Various reaction temperatures have been investigated to stabilize the CoSb3 phase obtained by a modified polyol process using a refluxing condenser. The resulting powders were cold-pressed and sintered in an evacuated-and- encapsulated ampoule for transport measurements. Single-phase CoSb3 could be produced for the reaction carried out at 448 K for a short duration of 15 min followed by evacuated-and-encapsulated sintering at 848 K for 5 h. In comparison with the sample sintered at 798 K, the sample sintered at 848 K exhibits lower resistivity and thermopower. Due to the sign crossover of the thermopower, the latter sample shows lower power factor for temperatures above 475 K.