MIT Produces The World’s Longest Flexible Fiber Battery

MIT Researchers developed a weavable, rechargeable ultra-long fiber lithium-ion battery that may have a future in making 3D-printed batteries in any shape.

The world’s longest flexible fiber battery, 140 meters long, was built to demonstrate that the material can be manufactured to arbitrarily long lengths. The work is described today in the journal Materials Today. The rechargeable battery can be woven and washed and could provide power for fiber-based electronic devices and sensors.

The new fiber battery is manufactured using novel battery gels and a standard fiber-drawing system, starting with a larger cylinder containing all the components, heated to just below its melting point. The parts are compressed to a fraction of their original diameter while maintaining all the original arrangement of elements. This is the first demonstration of a sub-kilometer-long fiber battery that is sufficiently long and highly durable to have practical applications.

The 140-meter fiber produced so far has an energy storage capacity of 123 milliamp-hours, which can charge smartwatches or phones. The fiber device is only a few hundred microns in thickness, thinner than any previous attempts.