Enhancing Thermoelectric Properties of Strontium Titanate Through In situ Growth of Carbon Nanotubes

Integrating low-dimensional materials, such as carbon nanotubes (CNTs), into thermoelectric matrices offers a promising route to enhance performance, yet achieving uniform dispersion and optimal interfacial properties remains a key challenge. In this study, a novel approach is demonstrated to boost the thermoelectric properties of strontium titanate (SrTiO₃) through the in situ growth of CNTs via chemical vapor deposition (CVD). By meticulously tuning catalyst composition, growth temperature, and catalyst concentration, the morphology and distribution of CNTs are optimized, ensuring homogeneous integration within SrTiO₃ matrix. Theoretical calculations show that Ni/SrTiO₃ compounds have an energy barrier of 0.41 eV for CH₄ dissociation into carbon atoms, much lower than that of Fe (100), Co (100), and Ni (100), thus facilitating CNT growth. Experimental results show that the 0.1-Ni sample improves electrical conductivity by ≈69% at room temperature, outperforming samples prepared by conventional mechanical mixing. Furthermore, the incorporation of in situ grown CNTs substantially reduces thermal conductivity by intensifying interfacial phonon scattering, achieving a thermoelectric figure of merit (zT) of 0.3 at 1000 K. These synergistic effects between enhanced electrical conductivity and reduced thermal conductivity establish a robust pathway for embedding low-dimensional carbon nanostructures into oxide thermoelectric materials, paving the way for next-generation high-performance thermoelectric composites.