Achieving high power factor and output power density in p-type half-Heuslers Nb1-xTixFeSb.

Improvements in thermoelectric material performance over the past two decades have largely been based on decreasing the phonon thermal conductivity. Enhancing the power factor has been less successful in comparison. In this work, a peak power factor of ∼106 μW⋅cm⋅K is achieved by increasing the hot pressing temperature up to 1,373 K in the p-type half-Heusler NbTiFeSb. The high power factor subsequently yields a record output power density of ∼22 W⋅cm based on a single-leg device operating at between 293 K and 868 K. Such a high-output power density can be beneficial for large-scale power generation applications.