A team of scientists in South Korea has developed a new way to make batteries last much longer and safer by improving ultra-thin lithium metal anodes.
Led by Professor Yu Jong-sung from the Department of Energy Science and Engineering at DGIST, the team discovered that adding a special chemical to the battery electrolyte can prevent dangerous problems that have limited the use of lithium metal batteries.
Their findings were published in the journal Advanced Energy Materials.
Lithium metal anodes are considered a powerful next-generation material for batteries. They can store over 10 times more energy than the graphite anodes used in most batteries today.
However, lithium metal comes with serious problems.
During charging and discharging, it can grow tiny needle-like structures called dendrites.
These dendrites can pierce through the battery and cause short circuits, fires, or explosions. In addition, the lithium metal expands and shrinks repeatedly, breaking down the protective layer on its surface and using up the electrolyte too quickly.
Using ultra-thin lithium metal—less than 50 micrometers thick—is important for making lightweight and compact batteries, especially in electric vehicles and drones.
But when the lithium is this thin, the problems become even worse.
So, researchers have been searching for ways to improve the protective layer, called the solid electrolyte interphase (SEI), which forms on the lithium surface. One promising idea is to use additives in the electrolyte to create a stronger, more stable SEI.
Professor Yu’s team tested a new additive called silver trifluoromethanesulfonate (AgTFMS). This chemical does two things at once: it creates silver (Ag), which helps lithium deposit more evenly, and lithium fluoride (LiF), which is strong and protects the anode.
This is the first time a single additive has been shown to create both helpful substances on the lithium surface.
By adding AgTFMS to the electrolyte, the team was able to prevent dendrite formation and make the batteries last over seven times longer than before.
They tested ultra-thin 20μm lithium metal anodes and found that they stayed much more stable over many charging cycles. Meanwhile, another team from Pusan National University used computer simulations to explain how silver improves the interaction with lithium.
Professor Yu said this simple method could make lithium metal batteries much more practical and speed up their use in electric cars, drones, and ships.
This breakthrough could lead to safer, longer-lasting, and more powerful batteries for the future.
