Power Generation from Nanostructured Half-Heusler Thermoelectrics for Efficient and Robust Energy Harvesting

We demonstrate a robust and high-power-density thermoelectric device fabricated using high-performance nanostructured bulk half-Heusler materials. A novel metal-ceramic composite was employed as electrodes to join the n-type and p-type half-Heusler elements to form a uncouple device. By matching the coefficient of thermal expansion of the nanostructured half-Heuslers, the composite electrodes reduce the interfacial shear stresses by 40% compared with the device using the conventional metal electrodes, which significantly improves the device reliability during operation under large temperature gradient. A three-dimensional finite element device model was built to calculate the device power output, efficiency, and thermal stress during operation. The uncouple device delivers an ultrahigh power density of 8.6 W/cm2 and an efficiency of 6.2% under a temperature difference of 570 °C, which are within 2% and 10% of the finite element simulation, respectively.