Metallic Zn decorated β-Zn4Sb3 with enhanced thermoelectric performance

A series of typical samples based on β-Zn4Sb3 have been prepared by spark plasma sintering. Single-phase β-Zn4Sb3 sample is found to be a brittle material. Many hole defects are found in single-phase sample after chemical etching. A small amount of excess metallic Zn reduces the hole defects and improves the thermoelectric performance of Zn-rich sample. The maximum ZT can reach 1.31 at 673 K. The improvement of performance can be attributed to hierarchical nanometer precipitates and interface stress. Introducing soft metal into particle boundaries is a potential solution to improve the performance of brittle polycrystalline thermoelectric materials.