Lithium-metal batteries are often described as the “next big thing” for electric vehicles and energy storage.
They can hold much more energy than today’s lithium-ion batteries—enough to boost an electric car’s driving range from about 400 kilometers to nearly 700 kilometers per charge.
But despite this promise, they’ve been held back by one major problem: safety.
Now, a team of Korean scientists has developed a breakthrough separator technology that could finally solve this issue while also doubling battery lifespan.
Researchers from POSTECH, Gyeongsang National University, and the Korea Institute of Energy Research engineered an ultra-thin membrane that acts like a tiny protective shield inside the battery.
Their work was recently published in Energy & Environmental Science. The membrane is only one molecular layer thick, yet it stabilizes both sides of the battery—the anode and the cathode—greatly reducing the risk of fires and explosions.
The main danger in lithium-metal batteries comes from a process that happens during charging. Lithium ions deposit unevenly on the anode, growing into thin, needle-like structures called dendrites.
Over time, these sharp structures can pierce the separator between the battery’s two electrodes, causing a short circuit. This is the kind of failure that can lead to smoke, fire, or even explosions.
To prevent this, the team modified a standard battery separator at the molecular level. They added fluorine and oxygen functional groups—tiny chemical structures that change how the surface interacts with the battery’s internal chemicals.
These added groups help manage reactions on both sides of the battery so that each electrode behaves more safely and more predictably.
On the anode side, the modified membrane encourages the formation of a uniform protective layer made of lithium fluoride (LiF). This layer smooths out lithium deposition and prevents dangerous dendrites from forming.
On the cathode side, the membrane stops the formation of harmful hydrofluoric acid, a substance that can damage the electrode and shorten the battery’s life. This means the single membrane provides two types of protection at once, helping the battery stay stable through many repeated charge and discharge cycles.
The results are impressive. Even under tough conditions—high temperatures, limited electrolyte, and a thin lithium layer—the batteries kept 80% of their original capacity after 208 cycles. Real-world pouch cells built with this design achieved energy densities between 385 and 1135 Wh, up to 1.7 times higher than commercial lithium-ion batteries.
Professor Soojin Park of POSTECH explained that this molecular-level design improves battery performance without requiring major changes to today’s manufacturing methods.
Professor Tae Kyung Lee noted that computer simulations helped reveal exactly how the new functional groups improve battery chemistry at the atomic level. Dr. Gyujin Song added that the new membrane is durable and safe enough for large-scale energy storage systems.
This single engineered membrane could help unlock safer, longer-lasting, and more powerful lithium-metal batteries—and bring the next generation of energy storage closer to everyday use.
