Microstructure and thermoelectric properties of carbon nanotube-carbon fiber/cement composites

The microstructure of the cement pastes was investigated by scanning electron microscopy. Thermoelectric properties of carbon nanotube-carbon fiber/cement composites were also measured during the heating and cooling process. Results show that carbon nanotubes act as fillers, which results in a dense microstructure of cement paste, when carbon nanotube is at a low content (less than 0.5% by mass of cement). The doping of CNTs leads to a highest increase (up to 260%) reaching 22.6μV/°C in the positive thermoelectric power of the cabon fiber/cement composites, when CNTs addition reaches 0.5% by weight of cement. Besides, the linearity and reversibility of the Seebeck effect was improved.