Carbon Foam/CaCl2·6H2O Composite as a Phase-Change Material for Thermal Energy Storage

Inorganic salt hydrates are promising phase-change materials (PCMs) for thermal energy storage due to their high latent heat of fusion. However, their practical application is often limited by their unstable form, dehydration, large supercooling, and low thermal conductivity. Porous melamine foam and its carbonized derivatives are potential supporting porous materials to encapsulate inorganic salt hydrate PCMs to address these problems. This work investigates the effect of pyrolysis temperature on the morphology and structure of the carbonized foams and their thermal energy storage performance. Pyrolysis of melamine foam at 700–900 °C leads to the formation of crystalline sodium cyanate and sodium carbonate particles on the foam skeleton surface, which allows the spontaneous impregnation of the carbon foam with molten CaCl2·6H2O. The form-stable foam-CaCl2·6H2O composite effectively suppresses supercooling and dehydration, demonstrating the efficacy of carbon foam as a promising supporting material for inorganic salt hydrate PCMs.