Lithium-ion battery yarn (Image: Wei Weng)Enlarge Photo
Could your car seats become large, comfortable batteries?
If experiments by scientists at Fudan University in Shanghai, China become reality, perhaps they could--as the group has developed battery technology that can be woven into fabrics.
According to Phys.org, researcher Wei Weng and his colleagues have designed and fabricated carbon nanotube composite yarns that can be wound around lithium-ion battery fibers and onto a cotton fiber, to create a lithium-ion battery.
As fibers with a 1mm diameter, these than then be woven into flexible textiles or cloth, like strands of any other material.
The main aim is to develop the technology into a generation of wearable electronics, since devices would then have a power source that wouldn't require pockets and compartments specially developed for existing solid batteries.
But naturally, where there is material, there's a potential battery--so automobile trim panels, seats, carpets and more are all potential batteries using the tech.
Some may be uncomfortable with the idea of sitting on a big battery, and Gizmag reveals the team is looking to ensure resulting battery fibers are safe. Weng says it's "the most important thing for wearable electronics", and that the team is investigating the "battery structure, the electrolyte and the packaging".
The battery yarn also needs to be flexible--like any other woven material. It needs to stretch, and be easy to fold--particularly for other functions the team sees as useful, such as materials used in hiking and camping where an extra source of power could be very useful indeed.
Further issues include measures to limit the expansion of silicon in the battery chemistry during charge and discharge cycles.
It's already a problem in existing battery experiments--the silicon's expansion damages the battery's internal structure--but even more of a problem in a woven material, that relies on certain important characteristics.
The team thinks it's got around this particular problem by incorporating those carbon nanotubes, which help clamp the expanding silicon in place.
The battery so far exhibits impressive electrochemical properties--0.75 mWh/cm energy density and capacity retention of 87 percent after 100 cycles.
Improvements are ongoing, and the team already has several goals--improving performance, developing large-scale production, and adding color-changing and stretchable characteristics.