Effect of Sb Doping on Thermoelectric Property of N-type Half-Heusler Compounds

Abstract

The effect of Sb doping on thermoelectric transport properties of N-type half-Heusler compounds Zr0.25Hf0.25Ti0.5NiSn1-xSbx (x=0, 0.002, 0.005, 0.01, 0.02, 0.03) was studied. Results show that with increasing Sb doping amount, the carrier concentration of the samples increases while the electrical resistivity decreases, especially sharply at low temperature range (~300 K). The Seebeck coefficient decreases, and the temperatures at which the Seebeck coefficient reaches climax move to higher ones. Therefore, the power factor increases by ~20%. The total thermal conductivity increases mainly due to the enhancement of electrical thermal conductivity, the lattice thermal conductivity remains almost unchanged. For the samples with x<0.01, the maximum ZT value is about 0.77 at 800 K, and among the samples, the one with x=0.005 performs the best in the whole temperature range.