Regulating thermoelectric properties of Eu0.5Ca0.5Zn2Sb2 through Mg dopant

CaAl2Si2 structure Zintl compounds are promising thermoelectric materials and have been extensively studied recently. In this study, Eu0.5Ca0.5Zn2-xMgxSb2 (0 ≤ x ≤ 0.3) compounds have been prepared by ball milling and spark plasma sintering. Results show that for Eu0.5Ca0.5Zn2Sb2, ZT has been improved about 20% compared with previously reported thermoelectric properties through the ball milling and hot-pressing preparation process. Moreover, the thermoelectric performance of Eu0.5Ca0.5Zn2Sb2 can be further increased through Mg substitution. Mg replacing Zn has a strong impact on phonon scattering, resulting in low thermal conductivity. A highest ZT about 1.05 is obtained in the Eu0.5Ca0.5Zn1.8Mg0.2Sb2 sample at 773 K. The obtained high thermoelectric performance in our work is comparable with other p-type Zintl thermoelectric materials, and this work provides a reference for the improvement of properties of other CaAl2Si2 structure Zintl thermoelectric materials.