Preparation of paraffin/silica–graphene shape-stabilized composite phase change materials for thermal energy storage

To achieve shape-stabilized phase change composites with high phase change material (PCM) load and high thermal conductivity, a series of mesoporous silica–graphene composites containing varying amounts of graphene were produced and used as supports, and paraffin was utilized as PCM. The characteristics of mesoporous silica–graphene supports and phase change material composites were analyzed using N adsorption and desorption, X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectrometer, differential scanning calorimetry, and thermogravimetry analysis. The pore size of the resultant mesoporous silica–graphene supports ranged from 4.63 to 5.92 nm, with a surface area of 564–664 mg. The results revealed that the composite containing 100 mg initial graphene oxide (PA/MS-100GO) had a maximum melting and solidification phase change enthalpy of 141.45 and 149.70 J g, as well as a maximum paraffin loading capacity of 85 wt%. The thermal conductivity of the PA/MS-100GO composite was 0.84 W m K, which is 342% higher than pure paraffin. Within operating temperatures of less than 250 °C, all composite PCMs produced in this study demonstrated high thermal stability and chemical compatibility. Consequently, the produced shape-stabilized composite PCMs with good thermal characteristics, thermal conductivity, and chemical stability are desirable for heat energy storage applications.