The lifespan of lithium metal batteries extended thanks to an eco-friendly nanofiber-based anode coating
How to overcome chemical and mechanical instability in lithium metal anodes, one of the major promises of next-generation batteries? Researchers at the Korea Advanced Institute of Science and Technology (KAIST) tackled this by using water and guar gum. The result? They succeeded in extending the lifespan of these electrodes by 750% compared to the current standard.
Lithium Metal Anodes: Pros and Cons
Lithium metal has only recently emerged as a material for anodes. Its strengths? A high theoretical specific capacity and low electrochemical potential, granting the battery ultra-high energy capacity (3,860 mAh/g).
However, lithium metal anodes also present several technical challenges related to charge-discharge cycles. For example, they are prone to the formation of dendrites (branched needle-like structures) and dead lithium. These issues lead to poor coulombic efficiency, significant volume variation, and internal damage, which in some cases can even result in dangerous explosions.
One solution in this area involves applying protective layers to the material’s surface, creating an artificial interface with the electrolyte. This approach has largely relied on toxic processes and expensive materials, with fairly limited practical results.
This is where the new study by Professor Il-Doo Kim from the Department of Materials Science and Engineering at KAIST, in collaboration with Professor Jiyoung Lee from Ajou University, comes into play. The team stabilized the growth of lithium dendrites and increased the lifespan of lithium metal batteries through a more eco-friendly approach.
An Eco-friendly and Biodegradable Protective Layer
The team developed a protective layer made of hollow nanofibers capable of controlling lithium ion growth through both physical and chemical means. The base materials? Guar gum and water (used as a solvent), employed in an electrospinning process. “The voids inside the fibers suppressed the random accumulation of lithium ions on the metal surface, stabilizing the interface between the lithium metal surface and the electrolyte,” explains KAIST. “As a result, lithium metal anodes with this protective layer showed a 750% increase in lifespan compared to conventional lithium metal anodes. The battery maintained 93.3% of its capacity after 300 charge-discharge cycles, achieving world-class performance.“
Researchers also confirmed that this natural protective layer completely decomposes in the soil within about a month, demonstrating its eco-friendly nature throughout the production and disposal process. Their study is published in Advanced Materials.
