The updated Zn–Sb phase diagram. How to make pure Zn13Sb10 (“Zn4Sb3”).
The Zn–Sb system contains two well-known thermoelectric materials, Zn1−δSb and Zn13−δSb10 (“Zn4Sb3”), and two other phases, Zn9−δSb7 and Zn3−δSb2, stable only at high temperatures. The current work presents the updated phases diagram constructed using the high-temperature diffraction studies and elemental analysis. All phases are slightly Zn deficient with respect to their stoichiometric compositions, which is consistent with their p-type charge transport properties. Either at room or elevated temperatures, Zn1−δSb and Zn13−δSb10 display deficiencies of the main Zn sites and partial Zn occupancy of the other interstitial sites. A phase pure Zn13−δSb10 sample can be obtained from the Zn13Sb10 loading composition, and there is no need to use a Zn-richer composition such as Zn4Sb3. While the Zn13−δSb10 phase is stable till its decomposition temperature of 515 °C, it may incorporate some additional Zn around 412 °C, if elemental Zn is present.