Efficient preparation of GO-modified regular spherical SiO2@CaCl2·6H2O phase change microcapsules for enhanced thermal energy storage

Hydrated salt phase change materials have great application value in passive thermoregulation fields due to their low phase change temperature . However, their practical applications are limited by problems such as leakage and phase separation, which require urgent attention. To solve these problems, in this study, a W/O emulsion system was constructed by sol-gel method, and microencapsulated composites with graphene oxide (GO) as the thermally conductive reinforcing phase, silica as the shell material, and calcium chloride hexahydrate (CaCl 2 ·6H 2 O, CCH) as the core material was prepared. The regular spherical SiO 2 shell layer effectively reduces the possibility of leakage of the core material. The excellent thermal conductivity of GO increases the thermal conductivity of the composites by about 41.14 % compared with that of pure CCH and maintains a latent heat of >114.1 J/g. The encapsulation of SiO 2 and the introduction of GO improve the thermal cycling stability of the composites. After 150 thermal cycles, the composites still had 96.5 % (110.1 J/g) latent heat and 99.6 % (0.708 W·m −1 ·K −1 ) thermal conductivity. The GO/SiO 2 @CCH microencapsulated composites had good temperature regulation. This study provides a promising solution for preparing hydrated salt-based shape-stabilized composites and expands their applications in construction and other fields.