Stanford Scientists Create a Lithium-Ion Battery That Won't Overheat

Scientists may have developed a battery that can't overheat. The new lithium-ion battery automatically shuts down before overheating and then restarts immediately when the temperature cools.

"People have tried different strategies to solve the problem of accidental fires in lithium-ion batteries," said Zhenan Bao, one of the researchers, in a news release. "We've designed the first battery that can be shut down and revived over repeated heating and cooling cycles without compromising performance."

A typical lithium-ion battery consists of two electrodes and a liquid or gel electrolyte that carries charged particles between them. Puncturing, shorting or overcharging the battery generates heat. If the temperature reaches about 300 degrees Fahrenheit, the electrolyte could catch fire and trigger an explosion.

Several techniques have been used in order to prevent battery fires, such as adding flame retardants to the electrolyte. Now, though, researchers have found a way to stop overheating while still maintaining the integrity of the battery.

The scientists coated spiky nickel particles with graphene, an atom-thick layer of carbon, and embedded the particles in a thin film of elastic polyethylene.

"We attached the polyethylene film to one of the battery electrodes so that an electric current could flow through it," said Zheng Chen, lead author of the new study. "To conduct electricity, the spiky particles have to physically touch one another. But during thermal expansion, polyethylene stretches. This causes the particles to spread apart, making the film nonconductive so that electricity can no longer flow through the battery."

The findings could be huge when it comes to creating batteries that are able to not overheat. This is particularly important to note when it comes to creating devices that could be damaged due to overheating.

The findings are published in the journal Nature Energy.

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