Biomimetic Hygroscopic Fibrous Membrane with Hierarchically Porous Structure for Rapid Atmospheric Water Harvesting

Sorption‐based atmospheric water generation (SAWG) is a promising strategy to alleviate the drinkable water scarcity of arid regions. However, the high‐water production efficiency remains challenging due to the sluggish sorption/desorption kinetics. Herein, a composite sorbent@biomimetic fibrous membrane (PPy‐COF@Trilayer‐LiCl) is reported by mimicking nature's Murray networks, which exhibits outstanding water uptake performance of 0.77–2.56 g g−1 at a wide range of relative humidity of 30%–80% within 50 min and fast water release capacity of over 95% adsorbed water that can be released within 10 min under one sun irradiation. The superior sorption–desorption kinetics of PPy‐COF@Trilayer‐LiCl are enabled by the novel hierarchically porous structure, which is also the critical factor to lead a directional rapid water transport and vapor diffusion. Moreover, as a proof‐of‐concept demonstration, a wearable SAWG device is established, which can operate 10 sorption–desorption cycles per day in the outdoor condition and produce a high yield of clean water reaching up to 3.91 kg m−2 day−1. This study demonstrates a novel strategy for developing advanced solar‐driven SAWG materials with efficient water sorption–desorption properties. Due to the sluggish sorption/desorption kinetics of absorbents, effective atmospheric water harvesting remains challenging. Herein, a biomimetic composite sorbent is reported that not only shows superior water uptake performance of 0.77–2.56 g g−1 at 30%–80% RH within 50 min, but also permits the release of 95% of adsorbed water within 10 min under one sun irradiation.