Enhanced thermoelectric properties of carbon fiber-reinforced cement composites (CFRCs) utilizing Bi<sub>2</sub>Te<sub>3</sub> with three doping methods
Xiaoyan Liu, Gang Liao, Junqing Zuo
Abstract
Bi2Te3 was incorporated in carbon fiber-reinforced cement composites (CFRCs) as thermoelectric-reinforced component via three different doping methods (uniformity volume mixing, gradient volume mixing, and gradient layer mixing), forming Bi2Te3 enhanced CFRCs. Seebeck coefficient and resistivity were measured for evaluating its thermoelectric properties. Scanning electric microscope (SEM) and three dimension video microscope (3-DVM) were applied to characterize the microstructure of prepared composites. SEM images showed that carbon fibers (CFs) overlapped on each other, resulting in a 3-D continuous electric conductive path. The introduction of Bi2Te3 enhanced the electric conductivity of the composites due to the quantum tunneling effect, which was beneficial to improve its Seebeck coefficient and the linearity and reversibility of the Seebeck effect. The thermoelectric performance of the composites was further improved by the synergetic effect of gradient effect and low dimension. Thermoelectric power (TEP) of the composite fabricated by gradient layer mixing method was enhanced as much as 10 times comparing to conventional CFRCs. The mechanism of the enhanced effect was also discussed.