Innovative Clay-Based Membrane Unlocks New Pathways for Lithium Recovery

Atomic structure of vermiculite membrane (Source: wiley)

Argonne National Laboratory is leading groundbreaking research into securing future lithium supplies. Lithium, the lightest metal on the periodic table, is vital for electric vehicles, mobile devices, laptops, and defense technologies because of its low weight and high energy density. As global demand rises sharply, concerns about supply shortages and vulnerable supply chains are mounting.
 
To address these challenges, scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, in collaboration with the University of Chicago’s Pritzker School of Molecular Engineering (PME), have developed an innovative membrane technology that efficiently extracts lithium from water. “The new membrane we have developed offers a potential low-cost and abundant alternative for lithium extraction here at home,” explained Seth Darling, Argonne’s chief science and technology officer for Advanced Energy Technologies and director of the Advanced Materials for Energy-Water Systems (AMEWS) Energy Frontier Research Center.
 
Currently, most lithium is sourced through hard-rock mining and salt lake brines in only a handful of countries, leaving the market vulnerable. Yet the majority of Earth’s lithium exists dissolved in seawater and underground brines, sources that have long been considered too costly and inefficient to exploit. Traditional extraction methods fail largely because lithium, existing as a positively charged cation, is difficult to separate from abundant competing ions like sodium and magnesium.
 
The Argonne team’s breakthrough lies in a new vermiculite-based membrane. Vermiculite, a naturally abundant clay costing about $350 per ton, was exfoliated into ultrathin layers—on the order of a billionth of a meter—and then reassembled into a 2D filter. To overcome the natural instability of clay layers in water, the researchers inserted aluminum oxide pillars between them, creating a stable, high-rise–like structure. This design prevented structural collapse while neutralizing negative surface charges.
 
By doping the structure with sodium ions, the researchers engineered a positively charged membrane surface that repels divalent magnesium ions more strongly than monovalent lithium ions. Further sodium ion modification reduced pore sizes, allowing smaller ions like sodium and potassium to pass through while selectively capturing lithium. “Filtering by both ion size and charge, our membrane can pull lithium out of water with much greater efficiency,” noted first author Yining Liu, a Ph.D. candidate at UChicago and AMEWS researcher.
 
This innovation could not only unlock new domestic lithium reserves but also extend to recovering other critical elements like nickel, cobalt, and rare earths, or even cleaning harmful contaminants from water. “There are many types of this clay material,” Liu added. “We’re exploring how it might help collect critical elements from seawater and brines or even improve drinking water purification.”
 
As access to clean water and secure supplies of strategic materials become defining global challenges, Argonne’s research underscores how advanced material science can power the technological empowerment and mission to achieve self-reliance in critical defence technologies.
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Source: Agonne National Laboratory