Thermoelectric transport properties of nickel-doped Co4−xNixSb11.6Te0.2Se0.2 skutterudites

In this paper, skutterudite compounds Co4−xNixSb11.6Te0.2Se0.2 (x=0, 0.05, 0.1 and 0.2) were successfully prepared by the solid state reaction and spark plasma sintering methods. The component phases and the chemical composition of all samples were characterized by the X-ray diffraction and the electron microprobe analysis, respectively. The Seebeck coefficient, electrical conductivity and thermal conductivity were measured in the 300–800 K temperature range. It is found that suitable amount of Ni dopant in the Co4−xNixSb11.6Te0.2Se0.2 system not only resulted in an improvement of the electrical conductivity but also a drop of the lattice thermal conductivity. The maximum dimensionless figure of merit of 0.83 was obtained at 800 K for sample Co3.8Ni0.2Sb11.6Te0.2Se0.2, representing a 23% improvement compared with that of the Ni-free sample.