Thermoelectric power factor performance of Bi85Sb15/graphene composite

Composite materials based on Bi85Sb15 with commercial graphene (Gr) nanoparticles have been synthesized by mechanical alloying and hot isostatic pressing. The effect of different amount of Gr nanoparticles (x = 0.02, 0.04, 0.06, and 0.08 wt %) on the thermoelectric properties of (Bi85Sb15)1-xGrx composite was investigated. X-ray diffraction and scanning electron microscopy were carried out for the structure characterization of the composites. Transport properties, including electrical resistivity, Seebeck coefficient, and calculated power factor, were investigated and their variations were discussed with regard to microstructures in the temperature range of 173-373 K. Resistivity significantly declines in the sample with x = 0.04 wt% Gr, and the enhancement was 7% at 230K and reached about 7.6% at room temperature. With 0.08wt% Gr, a high absolute value of the Seebeck coefficient was observed. The power factor reaches its maximum of 3.7 × 10-3W·m-1·K-2 with x = 0.08 wt% at 173 K. The results reflect that this synthesis process can be a powerful method of obtaining homogeneous Bi-Sb thermoelectric composite materials rapidly and at low cost. In addition, the demand for uniform coherent composites was significant because of their high-performance transport properties.