Study on moisture absorption and evaporation performance of dual-network hydrogels regulated by lithium chloride hygroscopic salt

Abstract In recent years, hygroscopic hydrogels have gained widespread application in atmospheric water harvesting (AWH) technologies. Sorbent materials, particularly those enabling atmospheric moisture capture, thermal energy storage, and passive cooling, represent promising candidates to address critical challenges associated with global water scarcity and energy transition. However, the large-scale deployment of such systems remains hindered by the reliance on unsustainable and costly sorbent materials. In this study, an innovative dual-network PSCL hydrogel was fabricated through a crosslinking-assisted vacuum freeze-drying methodology. This hydrogel demonstrates exceptional humidity regulation capabilities, achieving nocturnal atmospheric moisture adsorption followed by efficient solar-driven desorption during daylight. Systematic evaluations reveal that the PSCL hydrogel exhibits superior moisture adsorption and desorption capabilities across varying humidity levels. Remarkably, the hydrogel maintained structural integrity and performance stability over 12 consecutive adsorption-desorption cycles, demonstrating its potential for practical implementation in scalable atmospheric water harvesting systems. The integration of tailored porosity and photothermal responsiveness within the dual-network architecture provides a robust platform for optimizing water sorption kinetics and solar energy utilization efficiency. This work advances the development of sustainable hydrogel-based sorbents, offering a viable pathway to overcome the limitations of conventional materials in energy-efficient atmospheric water generation.