Improvement of thermoelectric performances of Bi_2Sr_2Co_(1.8)O_x textured materials by Pb addition using a polymer solution method

摘要

Bi_2Sr_2Co_(1.8)O_x ceramics have been prepared through a polymer solution method using polyethylenei-mine. From these powders, bulk textured materials have been prepared using a melt growth technique. Microstructure has been observed by scanning electronic microscopy (SEM) which has shown that samples are mainly composed by the thermoelectric phase, with small amounts of secondary phases. Electrical resistivity measurements showed very small values nearly constant with temperature, whilst thermopower increases from room temperature to 650 ℃. Power factor at 50 ℃ is about 0.15 Mw/K~(2-)· m and 0.30 at 650 ℃, which makes these ceramics good candidates for power generation applications.