Enhanced performance of Bi2Te3-based thermoelectric materials by incorporating Bi2Fe4O9 magnetic nanoparticles

Thermoelectric (TE) materials have been extensively investigated to solve the energy crisis and alleviate environmental pollution. Currently, n-type and p-type Bi2Te3 based are the only commercialized TE materials. However, their application has been severely limited by the low TE figure of merit (ZT) of p-type Bi2Te3-based TE materials. Here, we demonstrate that the TE performance of p-type materials could be improved by incorporating Bi2Fe4O9 magnetic nanoparticles. Bi2Fe4O9 magnetic nanoparticles could effectively scatter low-energy carrier and improve the carrier quality. The synergistic effect of boundary scattering and magnetic particles scattering lead to the increase of Seebeck coefficient and decrease of thermal conductivity. Finally, the maximum ZT value 1.1 is obtained at 393 K, which is 13% higher the pure sample. The average ZT value of the nanocomposite consisting Bi2Fe4O9 magnetic nanoparticles is 0.98 in the temperature range of 303–483 K, exhibiting an increase of 11%. Overall, the results indicate that magnetic nanoparticles with low saturation magnetic moment have positive effect on the performance of TE materials.