Synergy of reduced graphene oxide and metal oxides improves the power factor of thermoelectric cement matrix composites

Thermoelectric cement, a functional material that realizes the mutual conversion of thermal and electrical energy, has wide application prospects in energy harvesting and urban heat island effect mitigation. In this article, metal oxides and reduced graphene oxide (RGO) were added through ethanol liquid-phase mixing and pre-dispersion processes to the cement-based composites to enhance the thermoelectric properties. The addition of metal oxide increases the metal oxide/cement interface (metal oxide to cement interface, metal oxide to RGO interface, etc.). The presence of high-density interfaces hinders the carrier motion and leads to carrier scattering at the interfaces, which enhances the Seebeck effect of cement matrix composites. When the TiO2 content is 10.0 wt%, the RGO cement matrix composite achieved a power factor (PF) of 1.23 μWm−1 K−2, which was 10 times higher than before the addition. This study is a novel idea for further improving the thermoelectric properties of cementitious composites and promoting their practical applications.