A new solar-powered desalination device could help address society’s growing thirst for freshwater and energy. The device has specially engineered solar panels that pull potable water from seawater while also extracting salts, including lithium. Because it removes salts, the system does not produce harmful brine waste.

Researchers at the University of Rochester reported the device in the journal Light: Science and Applications. And in a recent related paper published in the Journal of Materials Chemistry A, the team showed that the panels can be tweaked to separate lithium from the recovered salts. The modified device extracted about half of the lithium from Great Salt Lake water samples.

According to the United Nations, the world has entered an “era of global water bankruptcy”. About 2.2 billion people do not have access to safely managed drinking water, and 3 billion live in areas where total water levels are declining or unstable.

Many parched regions of the world rely on desalination plants that convert seawater into fresh water. But the technologies used today are energy-intensive and expensive. They also generate large volumes of concentrated briny water that is discharged into the ocean where it can damage local ecosystems.

So the Rochester team took inspiration from the coffee ring effect to design their new solar desalination device. First, they etch small, black metal panels with ultra-fast lasers to make special solar panels. The textured black surface absorbs nearly all incoming sunlight and is very good at attracting water.

The patterned region quickly wicks water. As the device absorbs sunlight, the water evaporates and is distilled into fresh water. Meanwhile, the metal’s grooves are patterned in a way that they guide the salts and minerals outward to the edges of the active area, much like a coffee ring is formed as liquid evaporates and push the solid particles out in a circle.

For lithium extraction, the researchers embedded hydrogen titanate nanoparticles into the panel’s grooves. The particles selectively trap lithium ions selectively while other salts move to the passive collection zone.

“Mining lithium from the Earth has proven to be very taxing from an energy and environmental standpoint, so pulling lithium directly from saltwater could be a very important future route,” said Chunlei Guo, a professor of optics and physics, in a press release.

Sources:

• Luheng Tang et al. Additive-free and brine-discharge-free solar-thermal desalination with simultaneous complete mineral mining from ocean water. Light: Science, 2026.
• Luheng Tang et al. Rapid lithium extraction via solar-thermal interfacial evaporation with zero liquid discharge. Journal of Materials Chemistry A, 2026.

Image: University of Rochester photo / J. Adam Fenster