A Korean research team has directly observed at the nano level the moment degradation begins in lithium metal batteries, uncovering the fundamental cause of performance decline. The findings are being hailed as a critical turning point that could extend electric vehicle driving ranges and accelerate the commercialization of next-generation batteries.
The Korea Advanced Institute of Science and Technology (KAIST) announced Monday that a research team led by Professor Hong Seung-bum has identified the degradation mechanism of lithium metal anodes, a core component of next-generation batteries.
Lithium metal can store far more energy than conventional battery materials, making it a leading candidate for next-generation batteries. However, the rapid decline in performance through repeated charge-discharge cycles has been the biggest hurdle to commercialization. In particular, when lithium does not deposit evenly during charging and portions break away to form electrically disconnected "dead lithium," the result can be not only reduced battery performance but also heat generation and safety concerns.
The research team used in situ electrochemical atomic force microscopy (in situ EC-AFM), which allows real-time observation of changes inside a battery, to track the plating and stripping process of lithium at the nano level. The team found that lithium reactions do not occur uniformly across the entire surface but instead take place selectively at specific points.
In particular, in porous areas with rough surfaces or numerous microscopic holes, empty spaces readily formed after lithium was stripped away, creating electrically isolated "dead lithium" in the process. The team identified this phenomenon as the direct cause of battery performance degradation.
The research is significant in that it experimentally identifies where and how lithium metal batteries are damaged. It also confirmed that the "initial surface morphology" formed when lithium first deposits is a key factor governing the long-term lifespan of the battery.
The team projected that precisely controlling the surface structure to ensure uniform lithium formation could significantly improve battery life and stability. This points to a design direction that could simultaneously deliver longer EV driving ranges and the development of long-life next-generation batteries.
"This research is highly significant in that it directly confirmed the cause of battery performance degradation at the nano level," Professor Hong Seung-bum said. "It will serve as an important foundation for developing longer-lasting and safer next-generation batteries."
The study was selected as a cover paper in ACS Energy Letters, an internationally recognized journal in the fields of materials science, chemistry, and chemical engineering, and will be published in the February 24, 2026 issue.
