Low‐Energy Atmospheric Water Harvesting and Heat Recovery System Based on Vertically Stratified Structural Composite

Abstract Atmospheric water harvesting (AWH) technologies are critical for alleviating global freshwater scarcity. However, the high desorption energy consumption of conventional adsorptive materials severely hinders their widespread application, with enhancing adsorption‐desorption efficiency remaining a core challenge. This study presents a novel sorption‐type atmospheric water harvesting (SAWH) material fabricated via in situ crosslinking of sodium alginate with calcium lignosulfonate and loading of polypyrrole and LiCl, achieving two key performance enhancements: the vertically layered pore structure significantly reduces the diffusion resistance of internal water vapour. Under conditions of 95% relative humidity (RH), its adsorption capacity reaches as high as 5.7493 g g ⁻¹ . After moisture absorption in a 30% RH environment, the desorption rate can reach 0.02469 g g ⁻¹ min ⁻¹ . Notably, both of these performance metrics surpass those of many currently available advanced adsorbents. The integrated thermoelectric module constructs an adsorption‐desorption‐energy recovery closed‐loop system, achieving a water harvesting capacity of 2.42 L m ⁻² day ⁻¹ . During desorption, a maximum power density of 3.742 W m ⁻² can be attained, effectively reducing the energy consumption of atmospheric water harvesting through thermal energy recovery. These findings advance water treatment technology toward more efficient and energy‐saving practical applications, offering a promising solution for sustainable water resource management in arid regions.