Synthesis and thermoelectric properties of CoSb3/WO3 thermoelectric composites

In this study, nano-sized WO3 powder was dispersed into CoSb3 powder by ball milling and CoSb3/WO3 thermoelectric composites were fabricated using hot-pressing sintering. The results showed that the WO3 phase distributed uniformly in the form of clusters and the average size of cluster was lower than 4 μm. As the content of WO3 increased, the electrical conductivity and Seebeck coefficient of CoSb3/WO3 composites decreased. The thermal conductivity of composites decreased obviously which resulted from the phonon scattering by the WO3 inclusions locating on the grain boundaries of CoSb3 matrix. The highest thermoelectric figure of merit ZT = 0.40 was achieved at 650 K for CoSb3/2%WO3 composite.