Rapid In Situ Formation of Graphite-Enhanced Salogels via Cation-Triggered Self-Assembly for High-Performance Salt Hydrate Thermal Energy Storage

Salt hydrate-based polymer gels for phase change materials (PCMs) are promising for preventing leakage and imparting shape stability. However, gels based on covalent or dynamic covalent bonding often require multistep synthesis, resulting in increased fabrication complexity and cost. To address these limitations, we developed a one-pot formulation strategy for a CaCl 2 -based salt hydrate salogel. This approach utilizes Ca 2+ ions released from calcium chloride hexahydrate (CaCl 2 ·6H 2 O, CCH) to trigger rapid ionic cross-linking and form a robust polymer network that confines CCH. ATR-FTIR analysis confirmed stable polymer−ion interactions between Ca 2+ and polymer functional groups, including −COO − and −OSO 3 − . In addition, SEM-EDX mapping demonstrated effective physical entrapment of CCH within the interpenetrating polymer network. With the incorporation of graphite powder, the formulated salogels exhibited less than 1% latent heat decay over 300 thermal cycles and an 81% increase in thermal conductivity relative to pure CCH. This rapid gelation strategy provides a scalable framework for the large-scale production of salt hydrate PCM salogels with fast gelation, shape stability, high latent heat retention, and enhanced thermal conductivity.