Lithium batteries, while promising for the energy future, face major challenges related to their durability and safety. Researchers are continually looking for solutions to extend the life of lithium anodes, a key material for next-generation batteries. A recent innovation could be a game-changer in this area.
Researchers at the KAIST Institute recently announced advances in extending the useful life of lithium anodes. Their method, developed by Professor Il-Doo Kim of the Department of Materials Science and Engineering, in collaboration with Professor Jiyoung Lee of Ajou University, relies on the use of hollow, eco-friendly nanofibers to protect the anodes.
On December 2, the KAIST Institute, under the leadership of President Kwang Hyung Lee, revealed that their work had stabilized the growth of lithium and substantially improved the longevity of lithium metal batteries.
The limits of conventional protective techniques
Traditional protective layer technologies, which involve applying a coating to lithium to form an artificial interface with the electrolyte, often use toxic processes and expensive materials. These methods have provided only limited improvements in the life of lithium anodes.
To overcome these obstacles, Professor Kim's team proposed a new approach with hollow nanofibers. These nanofibers, manufactured by an environmentally friendly electrospinning process, use guar gum, extracted from plants, as the main material and water as the sole solvent.
The electrospinning process and guar gum
Electrospinning is a technique where polymer solutions are subjected to an electric field, making it possible to produce continuous fibers with diameters varying from a few nanometers to several micrometers. Guar gum, a natural polymer composed mainly of monosaccharides, regulates interactions with lithium ions through its oxidized functional groups.
The protective nanofiber layer effectively controls reversible chemical reactions between the electrolyte and lithium ions. The hollow spaces in the fibers prevent the random accumulation of lithium ions on the metal surface, thus stabilizing the interface between the lithium and the electrolyte.
Performance and durability
The results obtained with this new protective layer are impressive. Lithium metal anodes have seen their lifespan increase by almost 750% compared to conventional anodes. The batteries retained 93.3% of their capacity after 300 charge and discharge cycles, delivering world-class performance.
Additionally, researchers confirmed that this natural protective layer completely decomposes in about a month in the soil, proving its ecological nature throughout its life cycle.
Professor Il-Doo Kim explained: “ By leveraging physical and chemical protective functions, we were able to guide reversible reactions between lithium metal and electrolyte more efficiently and suppress dendrite growth, resulting in lithium anodes with unprecedented longevity characteristics. »
He added: “ As the environmental burden of battery production and disposal becomes a growing concern with the growing demand for batteries, this water-based manufacturing method with biodegradable properties will greatly contribute to the commercialization of new eco-friendly batteries. generation. »
Article : « Overcoming Chemical and Mechanical Instabilities in Lithium Metal Anodes with Sustainable and Eco-Friendly Artificial SEI Layer » – DOI: 10.1002/adma.202470373
