Synthesis of novel microencapsulated phase change material with SnO₂/CNTs shell for solar energy storage and photo-thermal conversion

Abstract In this study, In-situ precipitation reaction was used to prepare paraffin@SnO2/CNTs composite phase change materials. The paraffin@SnO2/CNTs composites material were prepared by using paraffin as a phase change core material, and tin dioxide and carbon nanotubes as composite shell materials. The microstructure, chemical composition and crystal phase structure of the composites were analyzed by Scanning electron microscope (SEM), Fourier infrared spectrum (FT-IR) and X-ray diffraction (XRD). The thermal performance and thermal stability of phase change materials were determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The microcapsule has a core–shell structure with a diameter of 2–5 μm. The encapsulation efficiency of the paraffin@SnO2/CNTs composite was calculated to be 42.94%. The slurry is formed by dispersing microcapsules in water, which not only greatly improves the specific heat capacity, thermal conductivity, visible light absorption, but also makes the effective receiving efficiency reach 91.79% at 40 °C, indicating that it is a promising heat transfer working slurry in the field of Direct Absorption Solar Collectors (DASC) system.