Improved thermoelectric performances in textured Bi1.6Pb0.4Ba2Co2Oy/Ag composites

Bi1.6Pb0.4Ba2Co2Oy thermoelectric ceramics with small Ag additions (0, 1, 3, and 5 wt%) have been textured using the laser floating zone method. Microstructure has shown a slight decrease on the secondary phases content and a better grain alignment in Ag added samples. These microstructural features are reflected in the thermoelectric properties, which have shown a significant decrease of electrical resistivity, when the Ag content is raised. In spite of a corresponding decrease of Seebeck coefficient, all the Ag-containing samples possess higher Power Factor values than the Bi1.6Pb0.4Ba2Co2Oy ones. Moreover, the maximum Power Factor values (about 0.36 mW/K2.m at 650 °C) have been measured in Bi1.6Pb0.4Ba2Co2Oy+3 wt% Ag samples, which are the best results reported in this family of materials.