PEG/SiO₂–Al₂O₃ hybrid form-stable phase change materials with enhanced thermal conductivity

The thermal conductivity of form-stable PEG/SiO₂ phase change material (PCM) was enhanced by in situ doping of Al₂O₃ using an ultrasound-assisted sol–gel method. Fourier transform infrared spectroscopy (FT-IR) was used to characterize the structure, and the crystal performance was characterized by the X-ray diffraction (XRD). Differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA) were used to determine the thermal properties. The phase change enthalpy of PEG/SiO₂–Al₂O₃ reached 124 J g⁻¹, and thermal conductivity improved by 12.8% for 3.3 wt% Al₂O₃ in the PCM compared with PEG/SiO₂. The hybrid PCM has excellent thermal stability and form-stable effects. - Highlights: • The PEG/SiO₂–Al₂O₃ hybrid form-stable phase change material (PCM) was obtained through the sol–gel method. • The inexpensive aluminum nitrate and tetraethyl orthosilicate were used as sol precursors. • This organic–inorganic hybrid process can effectively enhance the thermal conductivity of PCMs. • The PCM exhibited high thermal stability and excellent form-stable effects