Thermoelectric properties of LaFe3CoSb12 skutterudite materials with different nanostructures

Nanostructures with different morphologies could profoundly influence the electron and phonon transport in thermoelectric materials and thus their properties could be improved by tuning the nanostructures. The LaFe3CoSb12 skutterudite nano powders with different morphologies were fabricated via a hydro/solvo thermal route. The microstructures of the hot-pressed LaFe3CoSb12 bulks were characterized through X-ray diffraction (XRD) and scanning electron microscopy (SEM) and the effects of the nanostructures on the thermoelectric properties were investigated by measuring the electrical conductivity, the Seebeck coefficient and the thermal conductivity. The results suggested that the mixed morphology of nanorods and nanospheres could enhance the electrical conductivity largely although the Seebeck coefficient was decreased and the thermal conductivity was increased slightly. Differently, a higher Seebeck coefficient, a lower thermal conductivity and a lower electrical conductivity could be obtained for the LaFe3CoSb12 bulk with a single morphology of nanospheres. Consequently, the figure of merit of LaFe3CoSb12 bulk with a mixed morphology of nanorods and nanospheres could be increased by about 59% as compared to that with a single morphology of nanospheres.