The extraction of water from air is a promising way to supply fresh water, especially in remote, arid regions. This process can be supported by desiccant materials such as zeolites, metal−organic frameworks, or hygroscopic salts. Here we present a composite material that is able to absorb 660 kg of water per cubic meter of bulk material from air at 10 mbar water vapor pressure and 28°C. The material consists of calcium chloride incorporated into an alginate-derived matrix. A simple synthesis route leads to spherical beads of the composite with a diameter of approximately 2 mm. This macroscopic structure allows for good vapor permeability through packed beds. The collected water can be released at 100°C, potentially enabling a solar-driven application. In addition, the synthetic route uses cheap, non-toxic, and easily accessible materials allowing for widespread application.

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, CaCl2, 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.

A magnesium sulfate/polymer composite has been synthesized as active material for seasonal, thermochemical heat storage. It was found that the salt can store heat in the process of hydration/dehydration and the porous polymer matrix contributes due to adsorption and desorption of water. The composite shows high water uptake and a high gravimetric as well as volumetric heat storage capacity. The presented concept can be adapted to different salts and particle sizes of the respective salt within the matrix to investigate possible effects of particle size on heat of hydration and kinetic effects.