A new membrane mimics biological cell transport to extract lithium faster, cleaner, and more efficiently.The University of Texas at Austin designed bioinspired nanoscale artificial channels embedded in membranes. The tiny synthetic pores let lithium ions pass through while blocking competing ions (sodium, potassium, magnesium, and calcium). “Lithium is in our phones, our cars, and the power grid, but getting it out of the ground cleanly is still a hard problem. Our goal is a process that is faster, cleaner, and easier to run,” said Manish Kumar, a professor in the Fariborz Maseeh Department of Civil, Architectural and Environmental Engineering and the McKetta Department of Chemical Engineering.Synthetic cell-like channelsExisting purification methods depend on evaporation ponds, long processing timelines, and harsh chemicals that generate toxic environmental waste. Finding efficient, eco-friendly ways to separate lithium from these competing ions is important in times of growing supply chain issues.Off late, various solutions have already been emerging from around the world. In this new work, the Texas team turned to biology for a faster solution.It focused on artificial nanoscale channels that mimic the selective biological doors found in living cells. According to the study, the synthetic pores were made from ring-shaped pillar[5]arene molecules with specialized chemical “handles” at their entrances. This act as a precise bouncer, filtering out lithium ions from competing elements. Under an electric field, these channels achieve extraordinary precision. Conservative estimates place the channels’ selectivity at 94 times more likely to transport lithium over sodium, and over 280 times more selective against bulky magnesium ions. Overall, these tiny pores proved two to five times more selective for lithium than other recently reported artificial transporters.“We report the design of a class of bioinspired supramolecular membrane channels that achieve one of the highest overall Li+ selectivities reported to date for artificial transmembrane ion channels, with conservative lower-limit selectivity estimates of Li+/Na+ ≥ 94, Li+/K+ ≥ 136, Li+/Mg2+ ≥ 286,” the study paper noted.Further testing is neededFurther, molecular simulations reveal how the channels perform this atomic screening. As ions enter the narrow pathway, lithium easily trades its surrounding water shell for a favorable handoff with the channel’s chemical entrance. But heavyweight imposters like calcium and magnesium hold onto their water molecules too tightly. Stripping those water shells off requires too much energy, leaving them stranded outside while lithium glides through.The development could set a new performance benchmark for artificial ion channels, paving the way for faster, cleaner, and localized lithium extraction.“We now have a toolkit rather than a one-off result,” said Harekrushna Behera, a research scientist in Kumar’s lab. “By understanding how ions interact with the chemical groups at the channel entrance, we can work toward designing more selective channels for lithium and potentially other critical minerals.”Up next, researchers plan to pack millions of these channels into flexible polymer or lipid membranes to enable continuous, solvent-free separation. If they scale up and succeed in real-world brine tests, the bioinspired membranes could redefine direct lithium extraction (DLE). The technology holds promise for harvesting lithium from discarded EV batteries or even lining the inside of next-generation batteries to boost performance and safety.