Controlling Oxygen Vacancies in Sr_0.875La_0.1TiO₃ with the Nano Titanium for Optimizing Thermoelectric Performance

The nanosized titanium powder exhibits a strong oxygen capture ability, which can effectively increase the carrier concentration of SrTiO₃. However, it is essential to prevent oxidation before sintering. In this study, the impact of cold isostatic pressing (CIP) and calcination in an argon atmosphere on the microstructure and thermoelectric properties of Sr_0.875La_0.1TiO₃/nano Ti ceramics was explored. The results indicate that the carrier concentration of samples prepared by CIP can be significantly enhanced while simultaneously reducing the thermal conductivity through a notable grain size reduction of titanium oxide and augmentation of oxygen vacancy concentration. At 1073 K, the ZT value of the sample calcined in air and prepared by CIP was 0.22, exhibiting a 27% enhancement compared to that of the sample formed by dry press. Therefore, the combination of CIP and nanoscale Ti provides an efficient approach to manipulate the electrical and thermal transport properties of SrTiO₃ thermoelectric ceramics.