Bioinspired Hollow Fibers With Efficient Transport Channels for Wide Humidity Atmospheric Water Harvesting

ABSTRACT To address global freshwater scarcity, atmospheric water harvesting (AWH) offers a sustainable solution by extracting moisture from air. However, existing AWH materials struggle to combine high water uptake across a wide humidity range with portability. To resolve this limitation, a cotton‐like hollow fiber with low moisture vapor transmission resistance and fast adsorption kinetics is fabricated by coaxial wet‐spinning. The hybrid fiber employs sulfonated cellulose nanofiber (s‐CNF) and sodium alginate (SA) as hydrophilic network to provide effective moisture retention, and used carbon nanotube (CNT) for photothermal water evaporation. The hollow architecture provides additional sites for LiCl loading and efficient water vapor transport pathways. Therefore, the assembled s‐CNF/CNT/SA‐LiCl fibers demonstrate outstanding water adsorption performance across a wide humidity range (0.41 g/g at 11% RH and 5.00 g/g at 95% RH). Moreover, the hollow structure significantly enhances desorption efficiency, achieving a desorption rate of 5.88 kg/(kg·h), approximately twice that of solid fibers. The hybrid fibers can be woven into textiles and incorporated into flexible, wearable atmospheric water harvesting devices, achieving a water production rate of 4.55 g g day − 1 . This work establishes a novel inspiration for developing scalable, portable, and solar‐driven wide humidity water harvesting devices.