Imagine phones that last for days without recharging, drones that fly longer, and electric cars that travel farther on a single charge.
These possibilities are moving closer to reality thanks to a breakthrough from engineers at the University of Florida and their collaborators.
The team has developed an ultra-thin filter—just one atom thick—that could finally solve the biggest problem with lithium–sulfur batteries.
This type of battery has long been seen as a promising alternative to the lithium-ion batteries we use in almost everything today.
Lithium–sulfur batteries are lighter and can store more energy for their weight. But until now, they have been unreliable because the sulfur inside doesn’t behave well.
It forms long chains that clog the system, drain power, and quickly shorten the battery’s life.
The new filter works a lot like a microscopic coffee filter. It lets small lithium ions pass through easily, while blocking the larger sulfur chains that cause trouble.
Piran Kidambi, associate professor of mechanical and aerospace engineering at UF and lead author of the study, explains it simply: “Tiny lithium ions slip through easily, but bulky sulfur chains get blocked.”
The invention could have a huge impact. Today’s lithium-ion batteries are reliable but limited. A typical electric car battery weighs around 1,000 pounds and provides about 200 to 250 miles of driving range.
If that same weight of battery used lithium–sulfur instead, the car could travel much farther. For cellphones, that could mean going much longer between charges. For drones, lighter batteries would mean extra time in the air.
To create the filter, the researchers used a technique called chemical vapor deposition. They heated copper foil and exposed it to vapor, which triggered a reaction that left behind a layer of graphene—a material made of carbon only one atom thick.
This graphene sheet had tiny openings carefully designed to separate the lithium from the sulfur chains.
When tested, the results were dramatic. Regular lithium–sulfur batteries without the filter quickly lost power after repeated charging.
But the batteries with the atom-thin filter held almost all of their capacity through more than 150 charge and discharge cycles. “They performed quite well,” Kidambi said. “The others dropped off with each charge and discharge, but the ones with our filter held steady.”
The potential uses go beyond phones and cars. Freight trucks, trains, and even ships could benefit. The problem with larger vehicles is “weight compounding,” where the battery becomes so heavy it almost equals the weight of the cargo it is moving. A lighter, more powerful battery could change that balance.
Kidambi is clear that more research is needed before these batteries can be mass-produced and built into everyday devices.
But he sees this as a significant step forward. “There’s real scientific success in showing that we can solve a problem by engineering at the atomic level,” he said. “That is exciting for me.”
