Korean scientists have created a battery that’s so super-thin and flexible that it could one day lead to gadgets with big screens that can be folded away into your pocket.

A big limitation on the screen size of portable electronics is screen size. Since today’s phones, tablets and e-readers are rigid, there’s an upper limit to what can fit in a pocket or handbag. But the gadget can fold up, that’s another story.

We’ve had flexible screens for a while — both E Ink screens (common on ereaders) and OLEDs (on some phones) can be made flexible. However, other components aren’t quite so adaptable, especially the battery, which tends to be one of the largest single parts of any portable device. A folding battery would be a big step toward bendable gadgets.