Alginate‐Derived Salt/Polymer Composites for Thermochemical Heat Storage

Abstract Thermochemical heat storage composites based on inorganic salt hydrates embedded in a hydrogel‐derived polymeric matrix are presented. The synthesis offers the flexibility to obtain composites with different incorporated salts such as MgSO₄, MgCl₂, CaCl_2, and SrCl₂. The incorporated salts can release and store heat through reversible hydration and dehydration while the use of an alginate‐based matrix allows macroscopic structuring of the composite as beads that provide little pressure loss in packed beds. The synthesis is simple, can be scaled up and carried out in continuous flow. Charging temperatures below 150 °C, high volumetric storage densities of up to 1.50 kJ cm⁻³ (417 kWh m⁻³) combined with a macroscopic shape that allows easy vapor diffusion through packed beds present a major advance for heat storage materials based on salt hydrates.