A Highly Hygroscopic\nLiCl-Modified Gel for Efficient\nSolar-Driven Atmospheric Water Harvesting

In\nrecent years, solar-powered highly hygroscopic lithium chloride-modified\ngels were developed based on adsorptive atmospheric water harvesting\n(SAWH), an attractive method for obtaining fresh water from the atmosphere.\nIn order to enrich the atmospheric water collection materials and\nobtain high-performance atmospheric water collection materials, an\nSAWH composite material, LiCl (PAA-CMC-Na/DA-rGO@LiCl), with high\nefficiency, high stability, and low energy consumption has been designed\nand successfully prepared. The material consists of sodium carboxymethyl\ncellulose (CMC-Na) with high swelling performance and acrylic acid\n(AA) as the hydrophilic hydrogel network, dopamine-reduced graphene\noxide (DA-rGO) as the solar-thermal conversion medium, and high hygrometric\nlithium chloride (LiCl) as the hygrometric salt at low relative humidity\n(RH). A high water adsorption performance was obtained, with a water\nadsorption capacity of 0.819–3.019 g·g<sup>–1</sup> after 12 h under a wide humidity range of 30%–90% RH. At\n1 kW·m<sup>–2</sup> light illumination (1 kW·m<sup>–2</sup> is proportional to 1 sun), the surface temperature\nof the gel reached 69.5 °C after 60 min, and 79.1% of the adsorbed\nwater was released, showing good solar-thermal conversion and water\ndesorption performance. The material was cycled 10 times, which proved\nthat the composite hydrogel had good performance stability.