Enhancement in Thermoelectric Figure‐Of‐Merit of an N‐Type Half‐Heusler Compound by the Nanocomposite Approach

Abstract An enhancement in the dimensionless thermoelectric figure‐of‐merit ( ZT ) of an n‐type half‐Heusler material is reported using a nanocomposite approach. A peak ZT value of 1.0 was achieved at 600 °C–700 °C, which is about 25% higher than the previously reported highest value. The samples were made by ball‐milling ingots of composition Hf 0.75 Zr 0.25 NiSn 0.99 Sb 0.01 into nanopowders and hot‐pressing the powders into dense bulk samples. The ingots were formed by arc‐melting the elements. The ZT enhancement mainly comes from reduction of thermal conductivity due to increased phonon scattering at grain boundaries and crystal defects, and optimization of antimony doping.