Segmented Thermoelectric Oxide‐Based Module for High‐Temperature Waste Heat Harvesting

We report a high‐performance thermoelectric (TE) oxide‐based module using the segmentation of half‐Heusler Ti 0.3 Zr 0.35 Hf 0.35 CoSb 0.8 Sn 0.2 and misfit‐layered cobaltite Ca 3 Co 4 O 9+ δ as the p‐leg and 2 % Al‐doped ZnO as the n‐leg. The maximum output power of a 4‐couple segmented module at Δ T =700 K attains a value of approximately 6.5 kW m −2 , which is three times higher than that of the best reported non‐segmented oxide module. The TE properties of individual legs, as well as the interfacial contact resistances, were characterized as a function of temperature. Numerical modeling was used to predict the efficiency and to evaluate the influence of the electrical and thermal losses on the performance of TE modules. Initial long‐term stability tests of the module at the hot and the cold side temperatures of 1073 K and 444 K, respectively, showed a promising result with 4 % degradation for 48 h operating in air.