Entanglement‐Enhanced Sponge Hydrogels for High‐Efficiency Atmospheric Moisture Harvesting

Abstract Atmospheric water harvesting (AWH) is a promising strategy for freshwater production. Although hygroscopic polymeric gels (HPGs) are attractive AWH materials, their performance is limited by slow sorption–desorption kinetics. Herein, a new strategy is proposed to enhance moisture sorption–desorption kinetics by engineering an entanglement‐enhanced sponge hydrogel doped with lithium chloride (denoted as X D ‐PP@LiCl), which is synthesized via cosolvent‐induced gelation. By adjusting the dimethyl sulfoxide/water ratio ( X D ), the cross‐linking density of the poly(dimethylaminopropyl methacrylamide sulfonate) (PDMAPS) network is modulated, thereby constructing continuous microchannels. Such architectures enhance vapor diffusion efficiency while maintaining excellent structural integrity over multiple sorption–desorption cycles. Crucially, the synergy between PDMAPS and LiCl generates an internal osmotic pressure gradient, facilitating water transport and enabling continuous regeneration of active sites. Therefore, the X D ‐PP@LiCl hydrogel exhibits outstanding water uptake rates (0.95–1.48 g g −1 h −1 ) across a wide relative humidity (RH) range of 20–90%, a rapid desorption rate of 7.57 g g −1 h −1 at 30% RH, and robust cycling stability, retaining >97.6% of its initial water uptake capacity at 30% RH after 30 cycles. Furthermore, it achieves an excellent outdoor water production of 4.15 L kg −1 day −1 . This work provides a new strategy for designing high‐performance HPGs for AWH applications.