Optimized thermoelectric performance driven by A-site deficient in Sr_xLa_0.1TiO_3−δ/TiO_2−y composites

For thermoelectric applications at high temperatures, perovskite SrTiO₃ is a promising contender as an n-type oxide thermoelectric (TE) material. In this work, Sr_xLa_0.1TiO_3−δ/TiO_2−y composite ceramics were successfully synthesized by solid state reaction, using a combination of A-site cation vacancy and composite fabrication. Through X-ray diffractometer and scanning electron microscopy analysis, a complex microstructure composed of two kinds of titanium oxides was formed after reductive sintering and annealing. In addition, controlling the content of Sr vacancies in the Sr_xLa_0.1TiO_3−δ matrix increased the thermoelectric power factor (PF) by optimizing the weighted mobility in the composite, resulting in the highest PF of 425.8 μW m⁻¹ K⁻² and the maximum ZT of 0.16 for the Sr_0.875La_0.1TiO_3−δ/TiO_2−y composite through the synergistic optimization of electrical and thermal transport properties. The strategy proposed in this study of design A-site-deficient composites with nano-sized metal paved a new way to fabricate high performance oxide thermoelectric materials.