Reviewed by Lexie CornerMar 3 2025
A team of researchers from Rice University's Elimelech lab has developed a new lithium extraction technique that could transform the industry. The technique addresses the increasing demand for lithium, a key component in electric vehicle batteries. The study was published in Science Advances.
The researchers achieved nearly perfect lithium selectivity by repurposing solid-state electrolytes (SSEs) as membrane materials for aqueous lithium extraction. The highly ordered structure of SSEs allowed for unprecedented separation of ions and water in aqueous mixtures, despite being originally designed for fast lithium ion conduction in solid-state batteries, which lack other ions and liquid solvents.
This approach could significantly improve sustainable resource recovery by reducing the reliance on time-consuming and environmentally harmful traditional mining and extraction methods.
The challenge is not just about increasing lithium production but about doing so in a way that is both sustainable and economically viable.
Menachem Elimelech, Study Corresponding Author and the Nancy and Clint Carlson Professor, Civil and Environmental Engineering, Rice University
Researchers have been exploring direct lithium extraction technologies that recover lithium from unconventional sources, such as geothermal brines, industrial wastewater, and water produced by oil and gas, to make the process more environmentally friendly. A major challenge for these techniques has been ion selectivity, particularly when trying to separate lithium from other ions of similar size or charge, such as sodium and magnesium.
Elimelech and his team’s innovative method takes advantage of a key difference between SSEs and traditional nanoporous membranes. SSEs transport lithium ions through an anhydrous hopping mechanism within a highly ordered crystalline lattice, while conventional membranes rely on hydrated nanoscale pores to accomplish the same task.
This means that lithium ions can migrate through the membrane while other competing ions, and even water, are effectively blocked. The extreme selectivity offered by our SSE-based approach makes it a highly efficient method for lithium harvesting as energy is only expended towards moving the desired lithium ions across the membrane.
Sohum Patel, Study First Author and Postdoctoral Researcher, Massachusetts Institute of Technology
Using an electrodialysis setup, where an applied electric field drives lithium ions across the membrane, the research team—comprising Arpita Iddya, Weiyi Pan, and Jianhao Qian, postdoctoral researchers in Elimelech's lab at Rice—tested this phenomenon.
The results were impressive: the SSE consistently showed near-perfect lithium selectivity with no detectable competing ions in the product stream, even at high concentrations of competing ions. This is an achievement that traditional membrane technologies have been unable to match.
To understand the reasons behind the SSE's exceptional lithium-ion selectivity, the team used both computational and experimental methods. The results revealed that the SSE's rigid, densely packed crystalline lattice prevented larger ions, such as sodium and water molecules, from passing through the membrane. Magnesium ions were also rejected because they were found to be incompatible with the crystal structure and carried a different charge than lithium ions.
The lattice acts as a molecular sieve, allowing only lithium ions to pass through. This combination of highly precise size and charge exclusion is what makes the SSE membrane so unique.
Menachem Elimelech, Study Corresponding Author and the Nancy and Clint Carlson Professor, Civil and Environmental Engineering, Rice University
Although competing ions could not pass through the SSE, the researchers found that their presence in the feed solution reduced lithium flux by blocking surface sites available for ion exchange. The researchers believe this issue can be addressed with further material engineering.
As lithium shortages loom, industries that rely on lithium-ion batteries—such as the automotive, electronics, and renewable energy sectors—are searching for new sources of lithium and more environmentally friendly extraction methods. SSE-based membranes could play a key role in ensuring a steady supply of lithium without the environmental drawbacks of traditional mining.
“By integrating SSEs into electrodialysis systems, we could enable direct lithium extraction from a range of aqueous sources, reducing the need for large evaporation ponds and chemical-intensive purification steps. This could significantly lower the environmental footprint of lithium production while making the process more efficient,” said Patel.
The findings also suggest potential applications for SSEs in ion-selective separations beyond lithium.
“The mechanisms of ion selectivity in SSEs could inspire the development of similar membranes for extracting other critical elements from water sources. This could open the door to a new class of membrane materials for resource recovery,” said Elimelech.
Journal Reference:
Patel, K, S., et al. (2025) Approaching infinite selectivity in membrane-based aqueous lithium extraction via solid-state ion transport. Science Advances. doi/10.1126/sciadv.adq9823