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Scientists Create Stretchable Battery for Foldable and Rollable Phones

(Image credit: ETH Zurich)

That’s not rubber or black chewing gum. That’s a battery — a stretchable, twistable, foldable battery that can be the key to create thinner future foldable phones and rollable phones and displays.

Created by Markus Niederberger — a professor for multifuncional materials at the ETH Zürich technical university in Switzerland — the new stretchable battery uses a new type of material discovered by ETH’s doctoral student Xi Chen, who is the lead author of a paper about this invention published on September 6, 2019, in the journal Advanced Materials.

How the stretchable battery works

Chen came up with a new electrolyte — is the medium used by lithium-ions to travel in one direction or the other depending on how the energy is flowing. Like regular batteries, the stretchable invention is also built like a lasagna, using layers as this image shows:

(Image credit: ETH Zurich)

According to the paper, the current collectors for the anode and the cathode are made of bendable carbon, a material that is conductive to electricity.  Inside these surfaces there is a lawyer of microscopic silver flakes that arrange themselves like roof tiles. When you stretch or bend the battery, the flakes keep touching each. Even if some lose contact, the carbon layer ensure that the energy still flows into or out of the battery although, according to scientists, this happens slower than through the silver flakes.

The anode and the cathode are made of vanadium oxide and lithium manganese. In between these two there is a frame-like structure that also bends fill with the electrolyte gel that Chen discovered. This gel is made of water and a lot of lithium salt.

Future uses

The scientists claim that the battery is not ready for mass manufacturing yet because they have to find an adhesive to keep the layer sandwich sealed for a long time. Even while the electrolyte is not toxic and flammable — like today’s hard batteries’ — you don’t want your battery to spill water and salt into your phone’s guts.

But once they solve this problem, they applications are pretty obvious. If you have a battery that can be folded, stretched and rolled into any direction, you can basically go anywhere. Imagine a Galaxy Fold that is a continuous surface when unfolded rather than depending on two hard bodies and a hinge like the current one. Or a rollable tablet that you can put inside your jacket pocket. Or, talking about wearables, a jacket that can heat your body in the winter without the bulk of hard power packs or batteries that adapt to any shape in the future Apple AR Glasses.

According to Niederberger, Chen has returned to China to work for the battery industry. Knowing that, I wouldn’t find it surprising to see these things powering the all new Samsung Galaxy Scroll. I’d give it 5 years. A decade tops.