Thermoelectric performance of p-type Bi-Sb-Te materials prepared by spark plasma sintering

In the present study, p-type (Bi,Sb)2Te3 thermoelectric materials have been fabricated through the spark plasma sintering (SPS) method by using powders with various particle sizes. Electrical conductivity (σ), Seebeck coefficient (α), and thermal conductivity (κ) were evaluated in the temperature range of 300-500 K. The effect of annealing of the sintered samples on thermoelectric properties was also investigated. The maximum figure of merit ZT (ZT = α2σT/κ) of the sintered samples in the direction perpendicular to the pressing direction (with c-axis preferred orientation) was 1.15 at about 350 K, corresponding to be about 115% of that of the zone-melted ingot with the same composition in the same crystallographic orientation; while the bending strength was highly improved from about 10 to 80 MPa.