One small change in battery design could reduce fires, researchers say

Lithium-ion batteries are found in everything from smartphones to cars, and while they are generally very safe if stored and charged correctly, there are thousands of documented cases of them catching fire — sometimes with deadly consequences.

Lithium-ion batteries contain flammable electrolytes — liquid solutions of lithium salts dissolved in organic solvents that allow the electric charge to flow. The batteries can become unstable under certain conditions, such as physical damage like piercing, overcharging, extreme temperatures or manufacturing defects. When things go wrong, a battery can heat up and catch fire very rapidly, undergoing a dangerous chain reaction called a “thermal runaway.”

Commercial aviation is especially exposed to the problem, because of how ubiquitous battery-powered gadgets are on planes and how dangerous a fire in the cabin or cargo hold can be. In the US, the Federal Aviation Administration (FAA) has long prohibited carrying spare lithium-ion batteries in checked baggage and mandates that all batteries brought into the cabin must remain accessible. The agency recorded 89 battery incidents involving smoke, fire or extreme heat on passenger and cargo aircraft in 2024, and 38 in the first half of 2025.

These incidents can lead to the total loss of an aircraft, like the Airbus A321 that was gutted by flames in January in Busan, South Korea. The fire was likely started by a power bank stored in an overhead compartment, according to investigators, which has led some airlines to ban the devices.

But the risks of thermal runaways extend to homes, particularly vulnerable to e-bike or e-scooter battery fires, and businesses of all kinds: a survey conducted by insurance provider Aviva in 2024, among over 500 UK businesses found that just over half had experienced an incident linked to lithium-ion batteries, such as sparking, fires and explosions.

Researchers all over the world are working to solve the problem by developing safer batteries, for example by replacing the liquid electrolyte with a more fire-resistant solid or gel. However, such solutions require significant changes to current production lines, an obstacle to widespread adoption.

Now, a team of researchers from The Chinese University of Hong Kong has proposed a change in lithium-ion battery design that could rapidly integrate into current manufacturing methods, because it simply involves swapping chemicals in the existing electrolyte solution.

The method was detailed earlier this year in a study led by Yue Sun, now a postdoctoral fellow at Virginia Tech: “I think the most difficult thing for people to realize about batteries is that when you try to optimize performance, sometimes you compromise safety,” she said, explaining that increasing performance requires a focus on chemical reactions that happen at room temperature, while increasing safety focuses on reactions that happen at high temperatures.