Hygroscopic gels with Li+ leak-resistance and fast-cycling performance via multidentate ion locking and hierarchical pore design

GLDA chelator locks Li + via multidentate coordination, preventing salt leakage. • Combining directional freezing with in-situ polymerization rapidly locks pore structure. • High water uptake and a rapid adsorption, combining high capacity with fast kinetics. • Outdoor all-weather water harvesting, the produced water meeting WHO standards Sorption-based atmospheric water harvesting (SAWH) using hygroscopic salts offers promising decentralized freshwater supply, though deployment faces challenges like salt migration and adsorption-rate decay due to brine dilution. We introduce an ion-locking, thermoresponsive hygroscopic gel that enhances Li + fixation and vapor/liquid transport. Created via synergistic directional freezing and UV polymerization, the gel features an interpenetrating PNIPAM/PAA network with hierarchical macroporous architecture Aligned macrochannels facilitate low-resistance vapor diffusion and hierarchical macroporous architecture enhance water capture and storage. To prevent Li + loss, glutamic acid diacetic acid is grafted onto chitosan, providing multidentate chelation verified by XPS/Raman analyses and DFT calculations, securing Li + against hydration. PPCG-LiCl achieves high water uptake of 1.6 g g −1 at 30% RH and 6.8 g g −1 at 90% RH, with maximum sorption rates of 1.4 g g −1  h −1 and 2.9 g g −1  h −1 respectively, maintaining performance through long-term cycles. PNIPAM's LCST-triggered transition allows rapid solar desorption (≈80% water released in 20 min), supporting a fast-cycle SAWH device delivering daily yields of 2.53/3.92/5.85 g g −1 in various outdoor conditions, and generating water with ultralow Li + concentration (0.005 mg L −1 ). This innovation offers a practical material solution for stable, efficient SAWH.