Excellent thermoelectric properties of P-type cement-based composites through a universal defect engineering approach for large-scale energy harvesting

• A new method of preparing cement-based composites by changing the defect content. • The atmosphere treatment is applicable to a wide range of P-type metal oxides. • The combination of metal oxides and EG is a future trend with stable properties. When thermoelectric cement-based composites are used in roads and buildings, they effectively mitigate the urban heat island effect by absorbing heat from the environment and converting it into electricity, while reducing the surface temperature. Achieving large-scale applications requires cement-based composites with good thermoelectric properties. There have been many research efforts to obtain good thermoelectric properties, but the uncertainty of the enhancement effect is largely influenced by the researchers' process. The lack of a universal method to significantly improve the thermoelectric properties of cement-based composites has become a great obstacle for applications. In this paper, we obtained a universal approach by treating three P-type metal oxides Co 3 O 4 , CuO, and NiO in the oxidizing atmosphere. It was found that varying the defect content led to a significant improvement in the thermoelectric properties, obtaining excellent thermoelectric properties of P-type metal oxide cement-based composites, where the ZT values (measure of thermoelectric performance) increase by more than two times. This makes sense for stable large-scale energy harvesting in the future.