thermoelectric, cement composite, energy harvesting, figure of merit, PPMS
Thermoelectric (TE) cement composite is a new type of TE material. Unlike ordinary cement, TE cement can mutually convert thermal energy to electrical energy due to the addition of carbon fibers, metal oxide nanoparticles, etc. In hot summer or cold winter, the significant temperature difference between indoor and outdoor can be used by TE cement to generate electricity. On the other hand, given power input, the same material can provide cooling/ heating to adjust room temperature. Therefore, TE cement has certain energy-saving potential in the application of building enclosures and energy systems. Its ability to convert different forms of energy and use low-grade energy is conducive to the operation of net-zero buildings. In this study, a novel TE cement composite, MnO2 and graphite enhanced cement, was firstly fabricated. The surface morphology of the composites was analyzed by scanning electron microscopy. The performance indicators of TE materials include the power factor and dimensionless figure of merit ZT, which are calculated by Seebeck coefficient, thermal conductivity, and electrical conductivity. The values of these five TE properties were measured and calculated by a Physical Property Measurement System at different temperatures. Compared with the cement reinforced by graphite alone, it is confirmed that MnO2 nanoparticles have a positive effect on the enhancement of the TE performance for cement composites. The highest ZT of 5wt.% graphite and 10wt.% MnO2 enhanced cement composite prepared by the dry method is about 6.2 × 10-6 at 350 K.