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How do you make a thin, flexible battery that can’t explode? Just add Kevlar!

There are only a few things we want from the batteries that power our gadgets. It would be great if they lasted for a reasonable amount of time on a charge, that they aren’t the size of a small dog, and preferably, don’t explode when things inside go a bit wrong. Well, PHD students from the University of Michigan may have come up with one that incorporates all these elements, with the added bonus of some flexibility, by making a battery out of kevlar.

Nicholas Kotov, a professor at the University of Michigan, and Siu On Tung, a PhD student, decided to use kevlar nanofibers as a barrier between the electrodes of a lithium-ion battery. Using Kevlar could allow manufacturers to squeeze more electrodes into smaller packages, and thereby increase power while decreasing thickness. The material is also known for its ability to insulate well, which could prevent batteries from running too hot.

Michigan Engineering bulletproof batteries

The base for a Kevlar battery.

Sounds good, but what about those rare, but worrying explosions? Batteries explode because small pathways between electrodes emerge over time, causing it to short out. Here, the thin sheets of kevlar nanofibers insulate the electrodes and allow the current of lithium ions to travel along very specific paths. This stops fern-like patterns called dendrites from forming, which could eventually lead to the battery shorting out and exploding. The kevlar barrier keeps the ions on the correct path and prevents this disaster, thanks to incredibly tiny pores which don’t allow even the slimmest dendrite to pass.

Related: ProLogium’s flexy battery could power your next smartwatch

While the university’s Kevlar batteries are still at the experimental stage, thirty companies have already requested to use the technique, so we may have kevlar batteries as early as 2016. It’ll be difficult to say no to thinner, more powerful, and safer batteries.