Graphene enhanced thermoelectric properties of cement based composites for building energy harvesting

Abstract

Cement based thermoelectric materials can convert the available ambient heat absorbed by the building surfaces in summer into electrical energy. These materials can have an impact on the improvement of indoor climate of buildings, reduction of energy consumption and energy harvesting applications especially in the urban areas. In this paper, the thermoelectric properties of cement based composites with graphene nanoplatelets (GNP) inclusions were reported for the first time. GNP-cement mixtures were prepared by planetary ball milling and compressed subsequently to form bulk composites. We report the maximum electrical conductivity of 16.2 Scm−1 and Seebeck coefficient of +34.0 µVK−1 in this work. Hall measurement was performed to determine the material type and carrier concentration. It was found that all specimen exhibit p-type semiconductor behavior. Thermal diffusivity measurements were carried out using laser flash measurement technique. The highest figure of merit 0.44 × 10−3 was achieved at about 70 °C. Enhanced thermoelectric properties of graphene nanoplatelets cement based composites have a promising prospect in the urban heat island effect alleviation, thus saving electricity consumption and energy harvesting.