Structural Optimization and Design of Hydrate Salts in Energy Storage Systems

Inorganic hydrated salt phase change materials (PCMs) garner significant attention in energy storage, thermal management, and catalysis due to their distinctive structural characteristics, high energy storage density, cost‐effectiveness, and environmental benignity. However, inherent challenges such as pronounced supercooling, phase segregation, low thermal conductivity, and compromised cyclic stability hinder their practical deployment. To address these limitations, researchers have proposed innovative strategies including eutectic modification, microencapsulation, PCM‐based composite fabrication, and multilevel encapsulation, aiming to advance their commercialization potential. In this article, combined with the recent research progress, the performance optimization strategies of hydrate salts as phase change energy storage materials are reviewed, the basic properties and classification of hydrate salts, and most of the common problems existing in the process of use are introduced in detail. The influencing factors and improvement methods of supercooling, heat transfer and cycling stability are summarized. Meanwhile, inorganic hydrated salts still face several challenges in practical applications, such as performance degradation after long‐term cycling, corrosiveness, and stringent requirements for encapsulation materials. Finally, the current application status of inorganic hydrated salts is outlined, along with existing challenges and future development trends.