Preparation and Characterization of La-doped SrTiO₃ Ceramic Thermoelectric Materials

The sol-gel method was employed to synthesize the precursor for the preparation of La-doped SrTiO3 ceramic thermoelectric materials. The reducing atmosphere required during the ceramic sintering process is generated by the carbon formed through the in situ carbonization of organic components in the precursor, thereby eliminating the need for hydrogen. The ceramic samples prepared by synthesizing the precursor from the dried gel calcined at 430 ℃ exhibit lower pore density, higher sintering density, relatively high electrical conductivity, and an enhanced power factor, reaching 343 μW·m-1·K-2 at 600 ℃. Compared with samples prepared from precursors derived from dry gels calcined at 410 ℃, the present sample exhibits higher thermal conductivity. Nevertheless, it demonstrates a significantly enhanced thermoelectric figure of merit, reaching 0. 09 at 600 ℃. The xerogel-derived precursor synthesized by calcination at 410 ℃ contains a relatively high carbon content, which partially hinders the sintering process. Consequently, porous structures and numerous grain boundaries are observed in the ceramic samples. While this enhances phonon scattering, it simultaneously reduces carrier mobility.