The hoverboards that you may have seen during the recent holiday shopping season don't actually hover, but they do sometimes catch fire or explode -- a problem that could have been prevented with new battery technology developed by Stanford researchers.
The problem with those flaming hoverboards (which are really a kind of self-balancing scooter) comes down to their lithium ion batteries filled with highly flammable material that can overheat and ignite when something goes wrong. It's a relatively rare phenomenon that we've seen a few times in smartphones over the years as well.
The latest attempt to address the danger through better batteries comes from a team of Stanford chemical engineers. They've developed what they claim is the first lithium ion battery that automatically shuts down before overheating and then restarts itself once it's cooled off sufficiently.
The breakthrough involves using nanotechnology -- specifically by developing spiky nickel particles coated in graphene that can then be embedded in a thin plastic film.
"We attached the polyethylene film to one of the battery electrodes so that an electric current could flow through it," Zheng Chen, lead author of a study on the group's work, said in a release. "To conduct electricity, the spiky particles have to physically touch one another. But during thermal expansion, polyethylene stretches. That causes the particles to spread apart, making the film nonconductive so that electricity can no longer flow through the battery."
In other words, that layer of nickel and graphene-embedded plastic acts like a self-resetting circuit breaker. When it heats up, it expands, creating gaps between the tiny, current-carrying particles that disrupt the flow of electricity until things cool off enough that it then naturally contracts, reconnecting the circuit automatically.
The researchers' work was published in Monday's issue of the journal Nature Energy.
"We can even tune the temperature higher or lower depending on how many particles we put in or what type of polymer materials we choose," said co-author Zhenan Bao, who gives a more visual explanation of the approach in the video below. "For example, we might want the battery to shut down at 50 C [122 F] or 100 C."
Unfortunately, the technology is not yet commercially available. For now, it may be a good idea to keep a fire extinguisher next to your hoverboard, or review our advice on how to pick out the best and safest one.
If you really want to avoid a hoverboard fire, the safest choice might be to construct a real hoverboard track like the one Lexus created or this one that Stephen Beacham tried out. Since this type of hoverboard relies on super-cooled magnets to function, it might have the lowest fire risk of any form of "transportation" out there.