Recent Advances in Hydrogel‐Based Materials for Atmospheric Water Harvesting: A Review

In recent years, approximately two‐thirds of the global population has faced freshwater shortages. Due to its abundant resources, atmospheric water is considered an alternative water source. Atmospheric water harvesting (AWH) is emerging as a highly effective approach for freshwater collection to address the urgent global water shortage. Hydrogel‐based AWH technologies have attracted considerable attention in recent years, attributed to their unique three‐dimensional hydrophilic network structure and excellent water absorption properties. In this review, the adsorption and desorption mechanisms and adsorption kinetics of hydrogel materials are first explored extensively. Next, we highlight recent advances in state‐of‐the‐art biopolymer hydrogels (such as cellulose, chitosan, alginate, starch and their derivatives) and synthetic hydrogels for AWH. Thereafter, the potential applications of hydrogel‐based AWH in agricultural irrigation, electricity generation, and dehumidification are comprehensively discussed. Finally, this study further highlights the challenges and future research directions of hydrogel‐based AWH for sustainable and practical applications.