Enhanced Thermoelectric Performances of CNTs-Reinforced Cement Composites with Bi_0.5Sb_1.5Te₃ for Pavement Energy Harvesting

Driven by the huge thermal energy in cement concrete pavements, thermoelectric (TE) cement has attracted considerable attention. However, the current TE cement shows poor performance, which greatly limits its application. Herein, a series of Bi_0.5Sb_1.5Te₃/carbon nanotubes (CNTs) co-reinforced cement composites have been prepared, and their TE properties were systematically investigated. It was shown that the addition of Bi_0.5Sb_1.5Te₃ particles can effectively improve the TE properties of CNTs-reinforced cement composites by building a better conductive network, increasing energy filtering and interfaces scattering. The Bi_0.5Sb_1.5Te₃/CNTs cement composites with 0.6 vol.% of Bi_0.5Sb_1.5Te₃ exhibits the highest ZT value of 1.2 × 10^-2, increased by 842 times compared to that of the CNTs-reinforced cement composites without Bi_0.5Sb_1.5Te₃. The power output of this sample with the size of 2.5 × 3.5 × 12 mm³ reaches 0.002 μW at a temperature difference of 19.1 K. These findings shed new light on the development of high-performance TE cement, which can guide continued advances in their potential application of harvesting thermal energy from pavements.