High-Thermoelectric Figure of Merit Realized in p-Type Half-Heusler Compounds: ZrCoSnxSb1-x

We studied the thermoelectric properties of heavily Sn-doped ZrCoSb half-Heusler compounds, ZrCoSn x Sb 1- x ( x ≤0.15), to develop p-type thermoelectric materials. With increasing Sn content x , electrical resistivity decreased and the sign of the thermoelectric power changed from negative to positive. Thermal conductivity was reduced by an alloy scattering effect between Sn and Sb. A high figure of merit ( ZT ) was obtained: ZT = 0.45 at 958 K in ZrCoSn 0.1 Sb 0.9 . This ZT is approximately 2-fold higher than those of the p-type half-Heusler compounds that have been reported to date.