One of the locations on Earth where water is most conspicuously absent is the Atacama Desert in northern Chile. For years at a time, certain meteorological stations there do not record any discernible rainfall. The dirt has the hue of an aged bone. The air itself seems devoid of moisture. Nevertheless, throughout the course of the last two years, a baking sheet-sized gadget on the desert floor has been producing drinking water on a number of test days. Not from a desalination plant that uses the ocean, not from a well, nor from a river. from above. from the same dry, dry air that renders the Atacama seemingly uninhabitable.
Carlos Diaz-Marin, an assistant professor of energy science and engineering at Stanford’s Doerr School of Sustainability, is in charge of the team that created the device. The results, which were published in Nature Communications in May 2026, reveal a hydrogel that resolves a long-standing issue preventing this technology from being used practically. For more than 20 years, hydrogels—materials composed of salt and absorbent polymers—have been investigated as atmospheric water harvesters. The idea was always sound: these materials can retain multiple times their own weight in water by drawing moisture from the air even at extremely low relative humidity. Their rapid breakdown was the issue. The material deteriorated after roughly thirty cycles of moisture absorption and release. Because of this, the cost per liter of water generated was too high to be practical for any significant application.
The Stanford researchers changed the surrounding material after identifying a particular mechanism responsible for the degradation. After more than 190 cycles, the new formulation, which contains lithium chloride salt incorporated in polyacrylamide, a polymer also used in disposable diapers, holds together. That is more than eight months of continuous use without any discernible deterioration. The economics appear different due to the durability shift. According to Diaz-Marin, the cost of producing water is roughly one cent per litre, placing it in a level that is truly competitive with current solutions for people that do not currently have dependable access to clean water.
The gadget operates on a straightforward two-phase cycle that is solely powered by the difference between day and night. The hydrogel absorbs water vapor from the surrounding air at night as the temperature drops. Strongly hygroscopic, lithium chloride attracts moisture to itself even from very dry air. The gel is soaked by morning. Then, as the sun rises, an aluminum sheet that has been painted black to maximize heat absorption warms up next to the hydrogel, raising the temperature to the point where the gel releases the water it has held as vapor. On a cooler surface, that vapor condenses and drips into a collection container as drinkable water. No pumps, no energy, and no grid connection. Just a well-designed material and a temperature swing.
The Atacama test was designed to be the most challenging setting in which to illustrate this. If it functions there, as it does, filling the gel with water even under circumstances that should theoretically leave it empty, it ought to function in any desert area with limited access to water. Those areas are many. Approximately 2.2 billion people do not have access to safely managed drinking water, according to estimates from UNICEF and the WHO. The most severe shortages are found in portions of the Middle East, South Asia, and sub-Saharan Africa. The objective for this technology, according to Diaz-Marin, is areas where people currently trek for hours every day to gather water; in these circumstances, a low-cost, passively operated device that generates a few liters per day per square meter of material might have a real impact.
At this point, it’s important to be clear about what the technology can and cannot achieve. Modest amounts of water are produced by a single cookie-sheet-sized gadget. Larger arrays of the material or several devices working in parallel are needed to scale to fulfill the everyday needs of a family or small community. In addition to working on system-level optimization, the researchers have been working on deployment logistics with engineers in Chile and Ireland. Making the hydrogel operate in a lab is a different engineering issue than producing it at scale at the cost and quality required for field application, and that effort is still underway. These are typical gaps between a published proof of concept and a deployed solution, not reasons to discount the research.
