Using mesoporous carbon to pack polyethylene glycol as a shape-stabilized phase change material with excellent energy storage capacity and thermal conductivity

Abstract A novel shape-stabilized phase change material was successfully prepared using polyethylene glycol (PEG) as PCM and mesoporous carbon FDU-15 as support via the melting impregnation method. The structural and thermal properties of materials were measured by TEM, SEM, XRD, FT-IR, nitrogen adsorption-desorption isotherms and DSC, respectively. The maximum loading of PEG/FDU-15 reaches up to 75 wt%, and the corresponding crystallization ratio is 71%, which is superior to other mesoporous-based composite phase change materials. Molecular dynamic (MD) analysis showed that some PEG adhered to the pore wall with an amorphous structure which failed to crystallize, ultimately resulting in a gap between the measured latent heat and the theoretical value. It was interesting that the filling of PEG could stimulate the frequency shift of atomic vibration in FDU-15, which then just fell in the dominant vibrational zone of PEG, despite the suppressed atomic vibration of PEG after compounding. Accordingly, the thermal conductivity of the composite is more than 60% higher compared to pure PEG, which relates to the reinforced matching of the atomic vibration between the skeleton and PCM material. FDU-15 was applied to pack PCM for the first time and delivered a better thermal performance compared with other mesopore-based composite PCMs.