Thermoelectric figure of merit enhancement in cement composites with graphene and transition metal oxides

Having a high thermoelectric figure of merit is the essential prerequisites of a thermoelectric generator. In this study, a novel way to achieve a record high figure of merit for cement composites using graphene and metallic oxide nanoparticle inclusions is developed. This paper investigated the thermoelectric performances of graphene-metallic oxide cement composites fabricated by special dry mixing and pressing, followed by curing at ambient conditions. The experimental results indicate that the incorporation of oxide nanoparticles increases the Seebeck coefficient of the composites to 100 μV/K, which is factor ~3 higher than that of graphene based cement composites reported in our previous study. Improved Seebeck coefficient would effectively enhance the thermoelectric figure of merit. A maximum figure of merit as 1.01 × 10⁻² at 70 °C is obtained in this work, which is an order of magnitude higher than the other prior reported cement composites. The research findings provide an effective strategy to functionalize the cement based thermoelectric devices for the potential application in energy harvesting of smart buildings.