The researchers say their system can improve production at existing lithium facilities and unlock sources previously seen as too small or diluted to be worthwhile.

According to Nature Water the boffins came up with a s a set of porous fibers twisted into strings with a water-loving core and a water-repelling surface. When the ends are dipped in a salt-water solution, the water travels up the strings through capillary action.

The water quickly evaporates from each string's surface, leaving behind salt ions such as sodium and lithium. As water continues to evaporate, the salts become increasingly concentrated and eventually form sodium chloride and lithium chloride crystals on the strings, allowing for easy harvesting.

In addition to concentrating the salts, the technique causes the lithium and sodium to crystallise at distinct locations along the string due to their different physical properties. Sodium, with low solubility, crystallises on the lower part of the string, while the highly soluble lithium salts crystallize near the top. The natural separation allowed the team to collect lithium and sodium individually, a feat that typically requires the use of additional chemicals.

Professor of civil and environmental engineering and the Andlinger Center for Energy and the Environment at Princeton Jason Ren said: "We do not need to apply additional chemicals, as is the case with many other extraction technologies, and the process saves a lot of water compared to traditional evaporation approaches."