Preparation and performance study of hydrated salt phase change energy storage materials

Abstract To improve the thermal performance and cycling stability of hydrate salt phase change energy storage materials, composite materials were prepared based on anhydrous sodium sulfate, calcium chloride, and magnesium chloride using a solution mixing method and modified with nanosilica. The analysis showed that the phase change temperature of the material is 32.5°C, with a latent heat of 188.2 J/g. After 50 thermal cycles, the latent heat retention rate was 97.3%, with a phase change temperature deviation of only 0.6%. The optimal water content was found to be 40 wt%, achieving a balanced performance optimization. The results confirm the high energy storage capacity and long-term stability of the modified hydrate salt materials, providing theoretical support and optimization directions for energy storage technology applications.