Thermal storage

Hygroscopic hydrogels are emerging as low-cost, scalable sorbents for thermal energy storage, as well as atmospheric water harvesting, dehumidification, and passive cooling. Despite extensive research efforts, devices using these materials still exhibit insufficient performance, partly due to limited water vapor uptake of the hydrogels and slow kinetics. In this project, we aim to enhance both the water uptake and the sorption kinetics of hygroscopic hydrogels. To this end, we will characterize the swelling dynamics of hydrogels in aqueous salt solutions, study how the swelling affects the hydrogel salt loading, as well as understand the resulting vapor uptake of the synthesized hydrogel-salt-composites. We will combine these investigations with rational structuring of hydrogels for enhanced kinetics. The initial obtained water uptake results exceed previously reported values of other sorbents such as metal organic frameworks by over 100% and bring the water uptake of hydrogel-salt-composites close to the fundamental limit of typical hygroscopic salts. Our synthesis efforts also are combined with extensive modeling. These insights facilitate the design of hydrogels with exceptional hygroscopicity, thereby enabling sorption-based devices to tackle water scarcity and the global energy crisis.