Synthesis of SrTiO3 Fibers and Their Effects on the Thermoelectric Properties of La0.1Dy0.1Sr0.75TiO3 Ceramics

SrTiO3 fibers were fabricated by an in situ hydrothermal method using hydrated TiO2 fibers as both template and reactant. La0.1Dy0.1Sr0.75TiO3 powders containing x wt.% SrTiO3 fibers (x = 0, 1, 3, 5) were prepared by the sol–gel method and then sintered at 1450 °C under a reducing atmosphere (N2/H2 = 95/5). XRD analysis showed that the samples were mainly composed of SrTiO3 phase and a few Dy2Ti2O7 phase. TiO2 phase was detected in the samples with x = 3 and x = 5, and its peak intensity clearly reinforced with increasing x. With the addition of SrTiO3 fibers, the electrical conductivity increased significantly and the Seebeck coefficient kept almost unchanged, resulting in a high power factor of 1015 μW m−1 K−2 at 200 °C with a loading of 3 wt.% SrTiO3 fibers. Meanwhile, combined with low thermal conductivity, the sample with 3 wt.% SrTiO3 fibers showed the peak ZT value of 0.19 at 500 °C, which was 127% higher than that of La0.1Dy0.1Sr0.75TiO3.