Hybrid Polymer–Inorganic Salt Hydrate Materials: Applications for Heat Storage and Beyond

Polymer-salt hydrate hybrid materials called salogels combine the key properties of polymers, such as flexibility, with the high heat of fusion and inflammability and high salt content of the inorganic salts. These features make them promising materials for thermal energy storage and conversion, personal thermal management, anti-icing, and shape-morphing applications. However, further development is constrained by supercooling issues, poor control of mechanical properties, and limited reprocessability and scalability. This perspective briefly reviews recent applications of salogels, highlights the importance of advancing understanding of the specific mechanisms of interactions between polymer networks and inorganic salt ions to overcome these challenges, and outlines future directions in the development of polymer-salt hydrate hybrid materials. We suggest that by leveraging understanding of polymer-salt hydrate interactions, future research can focus on the rational development of processable polymer networks with controlled temperature-responsive gelation for specific salt hydrate or salt hydrate eutectics and the ability to suppress supercooling for robust thermal and mechanical performance. The perspective further identifies the importance of recruiting ML and additive manufacturing techniques for the accelerated development of polymer-salt hydrate hybrid materials of diverse chemistry and shapes for broader applications, which combine thermal energy storage with applications exploiting ionic mobility, such as electrochemical conversion, supercapacitors, and polymer electrolytes.