As the electric vehicle era enters full scale, demand is increasing for batteries that can travel farther and last longer. Lithium-metal batteries have been attracting attention as a next-generation technology capable of surpassing the capacity limits of existing lithium-ion batteries. However, during the charging process, needle-shaped crystals called “dendrites” grow, shortening battery life and increasing the risk of fire, which has been identified as the biggest obstacle to commercialization. A Korean research team has developed a key technology that can solve this challenge.
KAIST announced on the 24th that the research team led by Prof. Nam-Soon Choi from the Department of Chemical and Biomolecular Engineering and Prof. Seungbum Hong from the Department of Materials Science and Engineering, in collaboration with Prof. Sang Kyu Kwak’s team at Korea University, has developed a technology that resolves the most critical challenge of lithium-metal batteries, “interfacial instability,” at the electronic structure level.
Interfacial instability refers to the phenomenon in which the boundary between the electrode and electrolyte cannot be maintained uniformly during charging and discharging. As a result, lithium grows in needle-like dendrites, which leads to reduced battery cyclability, internal short circuits, and increased Thermal instability. This has been the fundamental cause preventing the commercialization of lithium-metal batteries.
The research team implemented an “intelligent protective layer” that allows lithium ions to move stably along the electrode surface by adding thiophene to the battery electrolyte. This protective layer has the characteristic that its electronic structure rearranges itself.
Like a smart traffic system that adjusts lanes according to traffic flow, the charge distribution inside the protective layer flexibly changes whenever lithium ions move, creating optimal pathways. The research team identified this mechanism through density functional theory (DFT) simulations and confirmed much higher stability compared to existing commercial additives.
As a result, they succeeded in effectively suppressing dendrite growth even under fast-charging conditions and significantly extending battery lifespan.
In addition, the research team directly observed the inside of the battery at the nanometer scale using in-situ atomic force microscopy (AFM). Even under high current conditions, they confirmed that lithium was deposited and removed uniformly on the surface, thereby verifying mechanical stability.
This technology can be applied to various cathode materials currently widely used, including lithium iron phosphate (LiFePO₄), lithium cobalt oxide (LiCoO₂), and lithium nickel–cobalt–manganese oxide LiNixCoyMn1-x-yO₂). Because it is not limited to a specific battery type and can be broadly applied across existing electric vehicle battery systems, it is expected to have significant industrial impact.
This achievement is meaningful in that it presents a breakthrough capable of fundamentally solving the ultra-fast charging problem—which has been the biggest barrier to lithium-metal battery commercialization—by simultaneously enabling fast charging within 12 minutes and high-current operation exceeding 8 mA/cm².
8 mA/cm² refers to a level at which 8 milliamperes of current flow per square centimeter of battery electrode area. In lithium-metal battery research, even around 4 mA/cm² is typically considered a “high current” condition, so this represents more than twice that level and corresponds to operating conditions close to real-world electric vehicle fast charging, rapid acceleration, and high-power driving.
Through this breakthrough, the technology is expected to be applied to various future industries requiring high-performance batteries, including ultra-long-range electric vehicles, urban air mobility (UAM), and next-generation high-density energy storage systems.
Prof. Nam-Soon Choi stated, “This research is not simply a material improvement but an achievement that solves the fundamental problem of batteries by designing the electronic structure,” adding, “It will become a core foundational technology for next-generation electric vehicle batteries that simultaneously achieve fast charging and long lifespan.”
This study was conducted by Jeong-A. Lee, Haneul Kang, Yoonhan Cho, Seong Hyeon Kweon, Seonghyun Kim, Syed Azkar UI Hasan, Minju Song, Saehun Kim, Eunji Kwon, Samuel Seo, Kyoung Han Ryu, Rama K. Vasudevan, Sang Kyu Kwak, Seungbum Hong, and Nam-Soon Choi, and was published on February 2 in the internationally renowned materials and energy journal InfoMat.
Paper title: Conjugation-mediated and polarity-switchable interfacial layers for fast cycling of lithium-metal batteries
DOI: http://doi.org/10.1002/inf2.70126
Meanwhile, this research was conducted with support from Hyundai Motor Company and the mid-career researcher program of the National Research Foundation of Korea.