Bi2Te3/Ti3C2Tx Nanocomposites and Its Thermoelectric Properties Study

In this paper, Bi2Te3 nanosheets were firstly synthesized by solvothermal method, and then Ti3C2T x (indicating O, F, OH, etc.) was introduced into bismuth telluride nanosheets with good thermoelectric properties as the second phase by the composite method of “ultrasonic dispersion-flash freeze-drying” combined with discharge plasma sintering technique, and the Bi2Te3/Ti3C2T x nanocomposites were successfully prepared. The effects of different contents of Ti3C2 T x on the thermoelectric properties of Bi2 Te3/Ti3C2 T x nanocomposites were also investigated. The samples were characterized and performance tested using scanning electron microscope, transmission electron microscope, thermoelectric test system, and laser thermal conductivity meter. The results show that the introduction of titanium carbide into the bismuth telluride nanomatrix increases the carrier concentration of bismuth telluride, leading to an increase in conductivity and a decrease in Seebeck coefficient, but the energy barrier scattering at the composite interface avoids a significant decrease in Seebeck coefficient; the nanocrystalline boundary between titanium carbide and bismuth telluride increases phonon scattering and interfacial thermal resistance and decreases thermal conductivity. The 1 vol% bismuth Bi2Te3/Ti3C2T x nanocomposites showed a 25% increase in thermoelectric figure of merit compared to the bismuth Bi2Te3 nanomatrix. 1 vol% Bi3Te3/Ti3C2T x nanocomposites had the highest ZT value of 0.908 at 432 K and the average ZT value of 0.87 in the range of376-511 K.