Effect of Mg-Doping on the Thermal Stability of Thermoelectric Zn4Sb3

The effect of 1 atomic% Mg substitution in Zn4Sb3 on the high-temperature thermal stability is investigated by multi-temperature high resolution synchrotron powder X-ray diffraction recorded both in atmospheric air and inert helium. The thermal stability of Mg0.04Zn3.96Sb3 is compared with an undoped Zn4Sb3 sample. About 85% of the original phase remains in the Mg-doped sample after three heating cycles to 625 K (both air and helium) while only similar to 40% is preserved in the undoped sample. Overall Mg0.04Zn3.96Sb3 heated in helium shows no clear improvement in the high-temperature thermal stability compared with the sample heated in air.