Thermoelectric cement-based composite materials can convert thermal energy in building environ-ments into electrical energy,and as a new energy conversion approach,have received widespread attention and research in recent years.There is a problem of mismatch between the optimal working temperature and environ-mental temperature in the application of thermoelectric cement-based composite materials,and the low thermo-electric conversion efficiency restricts the application of thermoelectric cement.This study incorporated expanded graphite(EG)/paraffin wax(PW)phase change composite materials prepared by melt blending into cement-based materials to prepare phase change expanded graphite/cement composite materials.The effect of the addition amount of phase change composites on the thermoelectric properties of cement-based materials was studied.The increase in the content of phase change composites regulates the temperature range for the optimal thermoelectric performance of cement-based composite materials.The test results show that the temperature point corresponding to the maximum thermoelectric performance is adjusted from 55℃to 60℃and 65℃.The corresponding Seebeck coefficient is-24.65,-30.97 and-30.90 µV/K.The power factor is 1.39,1.57 and 1.67 µW·m-1·K-2.Thermoelectric merit(ZT)value is 5.53×10-5,6.50×10-5 and 7.07×10-5.Phase change composites absorb heat during the phase change process,reducing the heating rate of cement-based materials,weakening the decrease in Seebeck coeffi-cient caused by an increase in carrier concentration due to temperature rise,adjusting the temperature range corresponding to the peak power factor of cement-based materials,and regulating the temperature range of use of thermoelectric cement-based composite materials.This study provides a new approach and method for improving the performance of thermoelectric cement-based composite materials.
paraffinexpanded graphitephase change materialscement based materialsthermoelectric pro-perties