Rapid fabrication and transport properties of n-type Co4−xNixSb12 via modified polyol process synthesis combined with evacuated-and-encapsulated sintering

Highlights: • Rapid fabrication method. • Co4−xNixSb12 synthesized via modified polyol process. • Reduced bipolar compensation of thermopower. - Abstract: Single phase of Co4−xNixSb12 compounds (x = 0.0, 1.5ε, 2.5ε, 3.0ε, 4.0ε, and ε = 0.03125) can be synthesized using the modified polyol reaction for 5 min., following by evacuated-and-encapsulated sintering at 853 K in a short period of time of 5 h. The sintered samples are characterized using X-ray diffraction, scanning electron microscopy, electrical resistivity, thermopower, and Hall measurements. Compared with the non-doped CoSb3, the power factor of Co4−xNixSb12 is enhanced up to 25 times by decreasing the electrical resistivity and reducing the bipolar compensation of thermopower. The simultaneous reduction of fabrication time and preparation temperature coupled with the comparable power factor with the same cobalt skutterudite system prepared via those expensive solid state methods should make this synthesis process of interest for commercial applications