Solvothermal synthesis of nano-sized skutterudite Co4-xNixSb12 powders

摘要

Nanostructuring is one of the effective approaches to lower the thermal conductivity of thermoelectric materials for improving its figure of merit．The nano-sized uniform skutterudite Co4-xNixSb12(x=0，0.2，0.3，0.5，0.6 and 1.0)thermoelectric powders were synthesized in triethylene glycol solution by using COC12，NiC12 and SbC13 as precursors and NaBH4 as reductant．Different synthesis conditions were studied to pursue pure and uniform skutterudite CoSb3 powders．The powders were characterized by X-ray diffraction(XRD)，field en．ssion scanning electron microscope(FESEM)and energy-dispersive X-ray(EDX)analysis．Experiment shows that a Ni-doped skutterudite Co4-xNixSb12 single phase was obtained at 290℃ for 12 h．The powders are of spherical form，small and uniform．As x increases from 0 to 1.0，the lattice parameter a increases from 0.9044 to 0.9065 nm and the particle size increases from 10 to 30 nm．Electrical properties of the bulk sample Co3 4Nio 6Sb12 prepared by spark plasma sintering(SPS)were studied．The highest power factor is about 4.28×10-4Wm-1K-2obtained at 613 K．