Sandwich-structured atmosphere water harvester with dual solar and electrical heating capacities for enhanced daily water production

Sorption-based atmosphere water harvesting (SAWH) is considered to be a promising solution to the global freshwater crisis. However, a high moisture absorption capacity, rapid moisture ab/desorption kinetics, and flexible desorption options are crucial for high-performance SAWH materials, but related research is scare. Here, a sandwich-structured atmosphere water harvester based on carbon cloth (CC), MXene nonosheets, sodium alginate (SA), and lithium chloride (LiCl) was fabricated via vacuum-assisted filtration and freeze-drying methods. On the one hand, the coordination of hygroscopic LiCl and porous film structure confer it with a high moisture absorption capacity and fast moisture absorption kinetics (moisture absorption of approximately 1.79 g g −1 after 4 h moisture absorption at 50 % RH, 25 °C); on the other hand, the conductive CC and photothermal MXene make it flexibly choose to release the absorbed water through solar irradiation (76 % of the absorbed water is released within 40 min, 1 kW m −2 ) or electrical heating (98 % of the absorbed water is leased within 10 min, 1.3 A). As a proof of concept, the daily water yield at 50 % RH with solar heating is approximately 7.01 kg kg −1 , which with electrical heating can reach 8.98 kg kg −1 in a lab environment, both of them are comparable to most of the hygroscopic salts-SAWH materials. The proposed sandwich-structured atmosphere water harvester with dual solar and electrical heating capacities has excellent moisture absorption performance and enriched water release routes, which has great means for designing of high-performance SAWH materials.