Shape-stabilized polyethylene glycol composite phase change materials based on dendritic mesoporous silica sphere support for thermal energy storage

Abstract

With the rapid development of renewable energy sources, energy storage technology based on solid-liquid phase change materials (SL-PCM) has received widespread attention due to its high-energy density, low cost and environmental friendliness. In this study, a simple synthesis procedure of dendritic silica microspheres (DMNSiO₂) was proposed by adopting a novel multiblock polyurethane surfactant as templating agent, and DMNSiO₂/PEG shape-stabilized phase change materials were prepared through vacuum impregnation using DMNSiO₂ as the mesoporous matrix. The DMNSiO₂ exhibited an inter-connective and uniformly distributed pore structure, which not only encapsulated and shaped the PEG material in a homogeneous manner, but also provided well-defined heat transfer channels. The optimal DMNSiO₂ for supporting PEG had a specific surface area of 876.4 m² g⁻¹, an average pore size of 8.39 nm and a maximum pore volume of 1.33 cm³ g⁻¹. DMNSiO₂/PEG-4 exhibited an excellent phase-change performance with superior phase change enthalpy of 151.54 J/g, which remained almost constant in the thermal cycling experiments with500 times of DSC scanning, The maximum encapsulation rate of DMNSiO₂/PEG is close to 75 %, and the thermal conductivity of DMNSiO₂/PEG composites were all improved comparing to pure PEG (28–57 %), which demonstrate their excellent thermal storage capability and good heat conduction properties. It has a broad application prospect in heat preservation building materials, solar energy storage, battery, and other thermal management fields.