Enhanced figure of merit of cement composites with graphene and ZnO nanoinclusions for efficient energy harvesting in buildings

In this work, we have reported the thermoelectric performance of graphene-zinc oxide hybrid cement composites for the first time. Nanostructured graphene and zinc oxide were incorporated into cement to increase the thermoelectric properties of cement composites. The as-received materials were blended, compressed, and subsequently cured at room temperature to make it bulk. On bulk samples, electrical conductivity, Seebeck coefficient, and thermal conductivity were measured. As a consequence of high electrical conductivity and the Seebeck coefficient, the composites exhibited a high value of thermoelectric efficiency. The maximum figure of merit (ZT) of 0.01 is obtained when the contents of graphene and ZnO are 10 wt%, respectively, by mass of cement. This ZT is the highest reported to date for the thermoelectric cement composites, a nearly 70% increase over the previous record with carbon based inclusions. High figure of merit is crucial for energy harvesting applications in future buildings.