Leak-free and shape-stabilized phase change composites with radial spherical SiO2 scaffolds for thermal management

Abstract

Microencapsulated core–shell structures have proven to be an effective means for realizing high-enthalpy and shape-stabilized phase change materials (PCMs), but the low heat and shear resistance of the shell material seriously restrict their practical application in functional materials. Here, leak-free and shape-stabilized PCMs were fabricated by a strategy of confinement of phase change media via capillary adsorption on synthetic radial spherical silica (RSSiO₂) scaffolds. The organic and inorganic components exchange the traditional core–shell positions, forming a new phase change composite with an inorganic material as the core layer. It not only endowed this composite with high-temperature regulation ability but also its enthalpy value was stabilized at 96.0 J g⁻¹ after the heat treatment process. More importantly, its heat-resistant stability was significantly improved, reaching above 300–350 °C. This indicates that the core structure of inorganic RSSiO₂ could not merely solve the inherent defects of conventional microcapsules but provides higher thermal stability as well, which is expected to be applied in high-temperature melt fiber spinning and electrical thermal management of devices.