Academics tout lithium extraction breakthrough

Researchers from the UK, France, and China have revealed findings about a new process for sustainable lithium extraction, which they say could help to solve ESG issues around existing production of the key battery metal.

Current ways of getting lithium are bad for the environment and more sustainable approaches are hard to perform on a large scale, the group warns. But it has now developed new membranes to pull lithium directly out of salty lake water using electricity, leaving other metal ions behind.

The new filtration membranes aim to enable direct lithium extraction from salt-lake brines through a selective electrodialysis process, efficiently separating lithium ins from other ions present in the brine. The filters can tell the difference between ions with one electrical charge, i.e. monovalent, and those with two charges, or divalent. This makes them very good at separating different types of salt ion, the research suggests.

The membranes use very tiny channels, smaller than a nanometre, lined with special chemical groups that interact with the ions as they pass through. Louie Lovell in Britton’s team applied pulsed field gradient nuclear magnetic resonance technique to characterise the water and ion diffusion in the sub-nanometre channels in the membranes.

The researchers found that the water diffusion co-efficients strongly depend on the channel sizes and the chemical groups within the membranes. These membranes can produce very pure lithium carbonate, of sufficient quality to be used in batteries.

“There is a critical demand for more sustainable processes addressing the global challenges of mineral availability and clean water supply,” says co-author Melanie Britton, from the UK’s University of Birmingham. “We believe our findings could lead to more efficient and sustainable lithium extraction, which is crucial for the batteries powering everyday devices such as smartphones, laptops, and electric vehicles.”

"Our research could reduce the environmental impact of lithium mining and contribute to the development of more efficient energy storage systems for renewable energy sources,” says Qilei Song from Imperial College London, who led the work. “There may also be applications in other areas of resource recovery; for example, critical metal recovery from wastewater, plastic and battery recycling.”

The group has published its findings in the Nature Water journal, under the title ‘Solution-processable polymer membranes with hydrophilic subnanometre pores for sustainable lithium extraction’, by Dingchang Yang, Yijie Yang, Toby Wong, Sunshine Iguodala, Anqi Wang, Louie Lovell, Fabrizia Foglia, Peter Fouquet, Charlotte Breakwell, Zhiyu Fan, Yanlin Wang, Melanie M. Britton, Daryl R. Williams, Nilay Shah, Tongwen Xu, Neil B. McKeown, Maria-Magdalena Titirici, Kim E. Jelfs, and Qilei Song.

Participating institutions were Imperial College London, University of Birmingham, University College London, University of Edinburgh, Institut Laue Langevin, Grenoble, France, and University of Science and Technology of China, Hefei.

New lithium projects make progress on both sides of Atlantic