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.