Hygroscopic wood sponge with dual phase change function for enhanced all-weather atmospheric water harvesting

Sorption-based atmospheric water harvesting (AWH) is a promising approach to relieve water scarcity in off-grid arid regions. Practical deployment remains limited by slow sorption kinetics caused by diffusion resistance and by intermittent desorption under diurnal and weather-dependent solar input. Here we report a hybrid solar and phase-change-material (PCM) hygroscopic wood composite (PHW) that integrates a water-sorption zone and an energy-management zone. The sorption zone uses a LiCl-embedded wood sponge with vertically aligned, multilayer channels to accelerate mass transport and shorten the time to equilibrium. The energy-management zone employs a PCM-based photothermal hydrogel to enhance solar-to-thermal conversion and store heat for sustained desorption. The PHW achieves a water uptake capacity of 0.59-3.03 g g^-1 at 15-90% RH and reaches equilibrium within 360 min. The PCM hydrogel provides a heat-storage enthalpy of 155.51 J g^-1 and an energy-conversion efficiency of 90.80%, enabling continuous water release under weak light and in darkness. In outdoor tests across cool winter and hot summer conditions and in different climate regions, a large-scale PHW array delivers a daily water yield of 0.96-1.72 L_water kg_sorbent^-1 day^-1 via continuous multi-cycle sorption-desorption. This hybrid sorption and thermal-management strategy advances all-weather AWH and improves real-world applicability.