Promising Bulk Nanostructured Thermoelectrics

Kurzfassung

Nanostructured bulk thermoelectrics have not been paid the attention they deserve for quite a long time probably due to the limitations of methods available for producing TE materials. We have established an international consortium and worked extensively on the fabrication, evaluation and modeling of nanostructured CoSb3 based skutterudite materials. Selection of material is based on the theoretically predicted lower thermal conductivity of the material which in turn could lead to an increase in the materials’ figure of merit. We proved the fact that nanostructured bulk skutterudites have much lower thermal conductivities than their larger size counterparts. The work also focused on improving the electrical conductivity by introducing substitutional and interstitial doping atoms into the lattice. The influence of addition of highly conducting metallic phases like Au, and Sb as well as insulator phases like CoSb2 and ZrO2 on the transport properties have been investigated on few samples. A very high ZT value of 0.65 was obtained for an unfilled skutterudite material with a combined doping of Ni and Te for Co and Sb respectively. This paper summarizes the work performed with the adapted synthesis approach, some representative results, and future prospects.