Enhancement of Thermoelectric Performance in BiSbTe Particulate Composites Including Ferroelectric BaTiO Nanodots.

An increasing number of studies have reported producing composite structures by combining thermoelectric and functional materials. However, combining energy filtering and ferroelectric polarization to enhance the dimensionless figure of merit thermoelectric remains elusive. Here we report a composite that contains nanostructured BaTiO embedded in a BiSbTe matrix. We show that ferroelectric BaTiO particles are evenly composited with BiSbTe grains reducing the concentration of free charge carriers with increasing BaTiO content. Additionally, as a result of the energy-filtering effect and ferroelectric polarization, the Seebeck coefficient was improved by ∼10% with a ∼10% improvement in power factors. The BaTiO phase can effectively scatters phonons reducing lattice thermal conductivity κ (0.5 W m K) and increasing to 1.31 at 363 K in BiSbTe composites with 2 vol % BaTiO content giving an improvement of ∼25% over pure BiSbTe. Our work indicates that the introduction of ferroelectric nanoparticles is an effective method for optimizing the of BiSbTe-based thermoelectric materials.