Magnetism-induced huge enhancement of the room-temperature thermoelectric and cooling performance of p-type BiSbTe alloys

Bi 2 Te 3 -Based alloys are the only thermoelectric material for commercial applications while their low performance is extremely difficult to improve. Herein, superparamagnetic Fe 3 O 4 nanoparticles (Fe 3 O 4 -NPs) are incorporated into a commercial p-type Bi 0.5 Sb 1.5 Te 3 matrix to improve the thermoelectric and cooling performance near room temperature. It is discovered that the Seebeck coefficient of the Fe 3 O 4 /Bi 0.5 Sb 1.5 Te 3 nanocomposites remarkably increased while the thermal conductivity significantly decreased because of the carrier multiple scattering and the enhanced phonon scattering induced by the Fe 3 O 4 -NPs, respectively. The maximum ZT reaches 1.5 at 340 K for the nanocomposite with 0.15 wt% of Fe 3 O 4 -NPs, being 32% higher than that of the matrix. At near room temperature, the huge cooling temperature difference reaches 5.4 K for a single-leg device made with the nanocomposite, increased by about 3 times as compared with the 1.8 K of the device made with the Bi 0.5 Sb 1.5 Te 3 matrix. This work reveals that introducing superparamagnetic nanoparticles is a universal approach to simultaneously enhance the thermoelectric and cooling performance of p-type BiSbTe-based alloys. Superparamagnetic Fe 3 O 4 nanoparticles remarkably enhance the room-temperature thermoelectric and cooling performance of BiSbTe alloys.