Controlling Precipitation and Dopant Effects To Achieve Promising Thermoelectric Performance in CaTiO3

Manipulating microstructures is of considerable importance for controlling the transport of heat and charge. Herein, the microstructure of CaTiO3 was controlled by adding Nb. Nb serves a dual purpose in the matrix by acting as a dopant, providing extra electrons, and as a phonon scatterer in the lattice. Additionally, it precipitates as a second phase in the Nb-doped CaTiO3 matrix. Through this approach, we achieved significant enhancements in the power factor, which increased from 2.81 μW cm–1 K–2 in pristine CaTiO3 to 7.67 μW cm–1 K–2 in CaTi0.85Nb0.15O3 at 1031 K. Additionally, we observed a reduction in the lattice thermal conductivity from 2.61 W m–1 K–1 in pristine CaTiO3 to 2.46 W m–1 K–1 in CaTi0.85Nb0.15O3 at the same temperature. As a result, a noteworthy 180% improvement in the overall zT was achieved. Remarkably, the zT value of CaTi0.9Nb0.1O3 in our work was found to be 88% higher than the values reported in the existing literature at 1031 K. This work provides a reference for optimizing the thermoelectric properties of CaTiO3-based materials by precipitating metal inclusions.