Effect of Refractory Tantalum Metal Filling on the Microstructure and Thermoelectric Properties of Co₄Sb₁₂ Skutterudites

We report a systematic investigation of the microstructure and thermoelectric properties refractory element-filled nanostructured Co4Sb12 skutterudites. The tantalum (Ta) metal-filled samples (TaxCo4Sb12 (x = 0, 0.4, 0.6, 0.8)) are synthesized using solid-state synthesis route. All composed single skutterudite phase. Meanwhile, nanometer-sized equiaxed grains present in Ta0.2Co4Sb12 Ta0.4Co4Sb12 samples, bimodal distributions elongated observed Ta0.6Co4Sb12 Ta0.8Co4Sb12 samples. dominant carrier type changes from electrons (n-type) to holes (p-type) with an increase Ta concentration power factor sample is increased 2.12 mW/mK2 at 623 K due 10-fold reduction electrical resistivity. lowest lattice thermal conductivity for indicates rattling action atoms grain boundary scattering. Rietveld refinement XRD data analysis Debye model confirm that occupies voids as well Co site. figure merit (ZT) ∼0.4 obtained sample, which comparable p-type skutterudites reported date. might be useful achieve both n-type legs filler atom could one replacements rare earth-filled improved properties.