Preparation and study of high-thermal conductivity phase-change energy-storage materials based on expanded graphite and pitch through high-temperature sintering

This thesis uses expansion graphite as the main raw material and asphalt as the binder. After sintering, the porous 3D network structure skeleton is obtained. Modified sodium acetate trihydrate (MPCM) was compounded with the prefabricated carrier to obtain a form-stable composite phase-change material (CPCM) with a thermal conductivity of 2.876 W<middle dot>m(-1) K-1, flexural strength of 12.4 MPa, compressive strength of 22.323 MPa, phase-change latent heat of 236.5 J/g and phase-change temperature of 48.8 degrees C. In addition, a commercial high thermally conductive (thermal conductivity >2.9 W<middle dot>m(-1) K-1) epoxy resin (ER) was coated on the surface of the CPCM to create a protected CPCM (PCPCM). Leakage tests and cycling tests show that the 1.0 mm epoxy coating gives CPCM good anti-leakage performance, with a weight loss of 0.013 % when held at 55 degrees C for two hours, while the PEGF skeleton prevents the expanded graphite from settling during long-term use. After 500 cycles, the latent heat of the CPCM was reduced by only 3.38 %, indicating that the structure can effectively prevent phase separation and segregation of phase change material. In this study, we successfully prepared CPCM that can be filled in thermal storage tanks and PCPCM that can be used directly as thermal storage bodies, broadening research on improved thermal conductivity and adsorption stereotyping of expanded graphite to facilitate the use of phase change energy storage materials and make them more promising for applications.