Fish-like nanorobots to help US engineers harvest lithium directly from seawater

Researchers in the U.S. have started developing fish-like nanorobots that can swim through seawater and harvest lithium in a bid to strengthen the domestic supply of the critical material. Led by Shiren Wang, PhD, and Jingjing (Jenny) Qiu, PhD, both professors at Texas A&M University in College Station, the project could make lithium recovery from seawater more efficient. It is supported by a USD one million award from the US Department of Energy (DOE). Rather than relying on conventional mining or underground brine extraction, the technology uses autonomous micro- and nanorobots. These tiny devices actively seek out and capture lithium ions from the seawater. The new approach could turn seawater into a stable alternative source of lithium for electric vehicles (EVs), batteries and energy storage. “Our goal is to develop a technology that supports a more reliable domestic lithium supply chain while reducing the environmental footprint associated with traditional extraction methods,” Qiu explained. Tiny ocean harvesters Lithium-ion (Li-ion) batteries are the leading choice for EVs because of their high energy density, long cycle life, and fast charging capabilities. However, traditional lithium extraction methods are struggling to meet the growing need. The global demand is projected to grow up to three times by 2030 and up to 4.2 times by 2035, in comparison with 2024 levels. Moreover, EVs and battery storage already account for about 61 percent of lithium consumption. They are expected to exceed 90 percent by 2024. To address the issue, the Texas A&M University researchers began designing tiny mobile robots that should boost lithium recovery from seawater. External stimuli, such as light, activate the robots and actively search for lithium ions as they swim. This, according to the team, improves the chances of capturing the mineral. Once their task is complete, they can be collected using magnetic fields. This allows the particles to be recovered and reused. “Unlike traditional mining that digs up land or pumps brine from underground and requires massive amounts of energy, these autonomous micro/nanorobots move freely through seawater to harvest lithium with virtually zero infrastructure footprint,” Qiu said. A smarter approach Even though the technology shows promise, the team acknowledged that several technical hurdles remain before it can be deployed at an industrial scale. One of the biggest challenges is selectively separating lithium from the other dissolved minerals naturally found in seawater. To prove that these robots can withstand the harsh marine environments while operating continuously and cost-effectively, the team will now focus on boosting their performance, testing lithium recovery efficiency, and developing methods to scale the technology for larger demonstration systems. The work combines expertise in micro- and nanorobotics, biomimetic movement, smart materials engineering, lithium recovery characterization, and marine system testing. “Seawater lithium recovery could provide a stable alternative source to address the growing global demand for lithium,” Qiu concluded in a statement. The project is one of 19 initiatives selected by the DOE to advance technologies that strengthen the U.S. critical mineral supply chain. Its goal is to create a novel pathway for lithium recovery and energy storage. Recommended ArticlesGet the latest in engineering, tech, space & science - delivered daily to your inbox.Based in Skopje, North Macedonia. Her work has appeared in Daily Mail, Mirror, Daily Star, Yahoo, NationalWorld, Newsweek, Press Gazette and others. She covers stories on batteries, wind energy, sustainable shipping and new discoveries. When she's not chasing the next big science story, she's traveling, exploring new cultures, or enjoying good food with even better wine.