Bend it, stretch it, power it: researchers unveil flexible battery

Researchers at Linköping University have developed a battery that can take any shape. (Thor Balkhed)

Imagine a battery as soft as toothpaste that can be stretched, twisted, or printed into any shape—and still power your device. That’s exactly what researchers at Linköping University in Sweden have created: a fully stretchable, rechargeable battery made from fluid electrodes and sustainable materials.

As more devices become part of our daily lives—from smartwatches to medical implants—the demand for flexible, body-friendly power sources is growing fast. “In ten years, it’s estimated that more than a trillion gadgets will be connected to the Internet,” says the study published in the journal Science Advances. “This could involve wearable medical devices, soft robotics, e-textiles and connected nerve implants.”

The problem facing wearable technology design is that most current batteries are rigid and bulky. They limit how small, soft or body-friendly devices can be. To fix that, the researchers created a new kind of battery made from thick, fluid-like materials called electrofluids.

“Fluids conform easily into any shape with minimal force, making them intrinsically deformable,” the study explains. That flexibility allows the battery to stretch up to twice its original length, bend, or be shaped using a 3D printer—without losing its ability to store and deliver power.

In testing, the battery worked for more than 500 charge cycles and remained stable even under heavy stretching. Although the voltage is currently low—0.9 volts—the team is looking at using elements like zinc or manganese to boost performance.

Another key feature of the battery is its focus on sustainability. It uses conductive plastics and lignin—a natural substance found in wood and often discarded in the paper-making process—as its main components.

“Repurposing a waste product into a value-added commodity such as a battery material would provide economic and sustainability merits,” the study says.

The design avoids using rare or harmful metals that are common in traditional batteries. This makes it not only flexible and functional, but also more environmentally friendly.

With wearable technology expanding quickly into health care, fitness and even fashion, soft, shapeable batteries could power a new generation of smart devices.

“Our work provides a technological solution for stretchable batteries that balances capacity and mechanical performance,” the researchers said.