Enhanced thermoelectric properties of cement-based composites with expanded graphite for climate adaptation and large-scale energy harvesting

Abstract

Thermoelectric cement-based composites offer a strategy, which can convert the thermal energy of solar radiation into electric energy directly for large-scale energy harvesting, reduce the pavement surface temperature and the total thermal energy discharged into the urban environment in summer by pavements and buildings. This paper investigated detailedly the thermoelectric properties of expanded graphite/cement-based composites (EGCC) fabricated by special dry-pressing and curing methods Hall coefficients of the cement-based composites were measured for the first time in this study. Results showed that EGCC exhibits a distinct semiconducting electrical behavior, the relatively high Seebeck coefficient at a temperature range of 30–100°C and extremely high electrical conductivity of 24.8S/cm for cement-based materials. The higher power factor and thermoelectric figure of merit 6.82×10−4 were then achieved in the case of keeping thermal conductivity of 3.213Wm−1K−1, while the EGCC held a high compressive strength (106.51MPa). The excellent thermoelectric property of EGCC has promising prospects for alleviating the urban heat island effect by harvesting and converting solar radiation thermal energy in large-scale, and thus decreasing cooling energy demand of cities.