Researchers have developed a lithium-ion rechargeable battery. This battery looks like an ultra-long fiber and can be woven into fabrics. A wide variety of wearable electronic devices can be enabled through the battery. The battery can also be used to make 3D-printed batteries of any shape.
The researchers see new possibilities for self-powered communications, sensing and computational devices. These can be worn as ordinary clothing. The batteries of these devices could also double as structural parts.
The team of the researchers produced world’s longest flexible fiber battery. The battery is 140 meters long. Scientists demonstrated that the materials can be manufactured to arbitrarily long lengths. This research has been described in the journal Materials Today. MIT postdoc Tural Khudiyev, former MIT postdoc Jung Tae Lee and Benjamin Grena SM ’13, Ph.D. are the lead authors of the research paper. MIT professors Yoel Fink, Ju Li and John Joannopoulos are the co-authors.
Team members have demonstrated fibers that have a wide variety of electronic components previously. These components include light emitting diodes, photosensors, communications and digital systems. Most of these components are weavable and washable. This makes them practical for use in wearable products. But before this new research, this was dependent on external power sources. Now, the fiber battery will enable such devices to be completely self-contained.
The new fiber battery can be manufactured by novel battery gels and a standard fiber-drawing system. This process will start with a large cylinder containing all the components. Then heat will be applied to just below its melting point. The material will be drawn through a narrow opening which will compress all the parts to a fraction of their original diameter. But this will maintain all the original arrangement of parts.
Other scientists have tried to create batteries in fiber form. They have put the key materials on the outside of the fiber. But the new system embeds the lithium and other materials inside the fiber and have a protective outside coating. This process makes it stable and waterproof. This is the first sub-kilometer long fiber battery. This battery is sufficiently long and highly durable to have practical applications.
The scientists were able to make a 140-meter fiber battery because there’s no obvious upper limit to the length. In the new fiber battery, they have incorporated a “Li-Fi” communications system. In this system, pulses of light are used to transmit data. The system also includes a microphone, pre-amp, transistor and diodes and these will establish an optical data link between two woven fabric devices.
When the scientists embed the active materials inside the fiber, the battery components have a good sealing. This means that the active materials are very well-integrated. During the drawing process, they will not change their position. The fibre battery is very thin and much more flexible. This makes it practical to use as a standard weaving equipment to create fabrics that need batteries as electronic systems.
The 140-meter fiber has an energy storage capacity of 123 milliamp-hours. This energy can charge smartwatches or phones. The fiber device only has a few hundred microns thickness. This is thinner than any previous attempts to produce fibre batteries.
The new system can embed multiple devices in an individual fiber. But all previous approaches needed integration of multiple fiber devices. The new system integrated LED and Li-ion battery in a single fiber. Scientists think that more than three or four devices can be combined together in future.
One-dimensional fibers can be used to produce two-dimensional fabrics. This material can be used in 3D printing or custom-shape systems to create solid objects. These objects will include casings that could provide both the structure of a device and its power source. The scientists have wrapped a toy submarine with the battery fiber to provide it with power. Incorporating the power source can improve efficiency and range of the product.
Scientists said this is the first 3D printing of a fiber battery device. If someone wants creates complex objects through 3D printing that have a battery device, then this is the first system that can achieve that. After printing, there will be no need to add anything from outside as all will be inside the fiber. It will be a one-step printing.
Scientists say now Computational units can be put inside everyday objects.