Promising Bulk Nanostructured Thermoelectrics

Nanostructured bulk thermoelectrics have not been paid \nthe attention they deserve for quite a long time probably due \nto the limitations of methods available for producing TE \nmaterials. We have established an international consortium \nand worked extensively on the fabrication, evaluation and \nmodeling of nanostructured CoSb3 based skutterudite \nmaterials. Selection of material is based on the theoretically \npredicted lower thermal conductivity of the material which in \nturn could lead to an increase in the materials’ figure of merit. \nWe proved the fact that nanostructured bulk skutterudites \nhave much lower thermal conductivities than their larger size \ncounterparts. The work also focused on improving the \nelectrical conductivity by introducing substitutional and \ninterstitial doping atoms into the lattice. The influence of \naddition of highly conducting metallic phases like Au, and Sb \nas well as insulator phases like CoSb2 and ZrO2 on the \ntransport properties have been investigated on few samples. A \nvery high ZT value of 0.65 was obtained for an unfilled \nskutterudite material with a combined doping of Ni and Te for \nCo and Sb respectively. \nThis paper summarizes the work performed with the \nadapted synthesis approach, some representative results, and \nfuture prospects.