Thermoelectric energy harvesting using cement-based composites: a review

Abstract In the modern era, cement and cement-based structures with additional functionalities are highly desirable. For example, the temperature difference induced between the outdoor and indoor surfaces of cement structures in buildings can be exploited for thermoelectric-based cement structures for energy harvesting. This article reviews the application of thermoelectric-based cement composites for energy harvesting and thermal sensing. These properties could be exploited in structures such as buildings, roads, housing, dams, and bridges. The enormous exposure of solar energy over the area of civil infrastructures is stored thermally within the construction materials, which is harvested when thermoelectric-based cement materials are used. First, the review describes the basic properties of thermoelectric materials and their applicability in cement composites. Furthermore, a broad classification of admixtures that are added in the cement composites for the enhancement of thermoelectric properties is made. The hole conduction improved significantly with the addition of carbon fibers in cement and thermoelectric power was recorded to be −17 μV/°C, which is much higher as compared to the pristine carbon fiber reinforced cement (−0.8 μV/°C). Steel fiber cement pastes show higher volume electrical resistivity than carbon fiber cement pastes even when steel fiber content is raised to 1% by mass of cement. Hence, development in thermoelectric-based cement composites by the addition of different admixtures is summarized. Finally, the challenges for the more efficient and large-scale operation of thermoelectric-based cement composites are mentioned and discussed for further improvements.