An Energy Harvesting Perspective of a Perovskite Based Thermoelectric Module: Fabrication and Evaluation

Abstract

Oxide thermoelectric materials based on n-type perovskite Ca0.99Dy0.005Lu0.005MnO3 and p-type layered Ca3Co4O9 were developed and their application towards energy harvesting from waste heat was demonstrated. The n- and p-type oxides were synthesized by a sol–gel route followed by hot-press sintering to achieve densities that were 95–98% of the theoretical values. The doping concentrations in the thermoelectric materials were optimized to achieve lower electrical resistivity with moderate Seebeck coefficients that yielded power factors close to 550 μW m−1 K−2 at 950 K. A 14-element thermoelectric (TE) module was fabricated by connecting the developed n- and p-type oxide materials electrically in series and thermally in parallel. The electrical connectivity was achieved using Ag conductive paste followed by sandwiching the n and p-type materials between two insulating alumina plates. The module was tested in a simulated environment of hot gas flow with hot-side temperatures up to 623 K. The module generated an output voltage of 0.34 V with a power density of 0.9 mW cm−2 at 623 K.