Currently, over 75% of lithium comes from a handful of countries such as Australia, Chile, and China through hard rock mining and salt flat evaporation ponds, according to the International Energy Agency (IEA).
This geographic concentration poses significant supply chain risks. Meanwhile, estimates suggest that oceans hold over 230 billion tons of dissolved lithium—far exceeding known land-based reserves .
The Argonne team’s innovation addresses the core challenge of separating lithium from chemically similar ions, such as magnesium and sodium, which are more prevalent in seawater and geothermal brine.
Using vermiculite a clay used in potted planting, the researchers engineered a 2D membrane by slicing the mineral into nanometer-thick layers. They then stabilized these layers with nanoscale aluminum oxide pillars, creating a structure that resists collapse in water and enables ion-selective filtration.
A key advance lies in the membrane’s ability to manipulate surface charge. By introducing sodium ions, the researchers tuned the membrane to repel magnesium ions (which carry a +2 charge) more strongly than lithium ions (+1 charge). This charge-based repulsion improves lithium selectivity without the need for energy-intensive chemical treatments or high-pressure filtration.
This method may offer significant economic and environmental advantages. Vermiculite costs around $350 per ton—far less than engineered synthetic membranes—and the process operates under ambient conditions, making it potentially scalable for industrial use. According to Argonne, nearly half of the lithium-related recalls and failures in EVs could be traced back to materials issues, further emphasizing the need for more secure domestic sources of critical minerals.
Beyond lithium, the research team sees potential for the membrane to extract other strategic elements, such as nickel and cobalt, or even to remove contaminants like lead and arsenic from drinking water—a major issue in many U.S. communities. The work adds momentum to a growing field of “ion-selective” membrane technologies aimed at reclaiming valuable materials from waste streams while supporting water sustainability.
As energy systems transition toward electrification, innovations like Argonne’s lithium-selective membrane may help reduce dependence on geopolitically sensitive resources and lay the groundwork for cleaner, more secure supply chains.
This research was funded by AMEWS, an Energy Frontier Research Center funded by the DOE Office of Basic Energy Sciences.