World’s Longest Flexible Fiber Battery Produced

Researchers have produced a flexible fiber lithium-ion battery 140 meters long. For those not using the metric system, that is just over 459 feet.

The battery can be used in wearables and could even lead to 3D-printed batteries in nearly any shape. This breakthrough opens the door for self-powered devices worn like clothing or batteries that serve as structural parts.

You can view the paper entitled “Thermally drawn rechargeable battery fiber enables pervasive power” in Materials Today.

While we already have wearables that include electronic components, light-emitting diodes (LEDs), photosensors, communications, and digital systems, they all rely on external power sources. This new fiber battery can enable self-contained, weavable, and washable devices as the lithium and other materials are embedded within the fiber with a protective outer coating. The fiber is only a few hundred microns thick.

The team sees no apparent upper limit on the length of their fiber battery and claims they can scale into the kilometers.

The 140-meter fiber produced by the team can store 123 milliamp-hours—enough power to charge smartwatches and smartphones.

“The beauty of our approach is that we can embed multiple devices in an individual fiber,” says MIT postdoc Jung Tae Lee, one of the authors of the paper. They demonstrated this by integrating LEDs and a Li-ion battery in a single fiber. Lee believes they can combine more than three or four devices into a single fiber in the future.

In addition to using the fiber in fabric, the material can be used in 3D printing applications, providing power and structure in one object, like the submarine pictured above.