Scientists at Nanyang Technological University (NTU) in Singapore, Tsinghua University in China, and Case Western Reserve University (CWRU) in the USA claim to have developed a fiber supercapacitor that can be woven into clothing and power wearable medical monitors and communications.
The device packs an interconnected network of graphene and carbon nanotubes so tightly that it stores energy comparably to some thin-film lithium batteries.
The product's developers believe the device's volumetric energy density is the highest reported for carbon-based microscale supercapacitors to date -- 6.3 microwatt hours per cubic millimeter.
The device also maintains the advantage of charging and releasing energy much more quickly than a battery. The fiber-structured hybrid materials offer accessible surface areas and are highly conductive.
The researchers have developed a way to continuously produce the flexible fiber, enabling them to scale up production for a variety of uses. They've made 50-meter long fibers, and they see no limits on length.
The scientists envision the fiber supercapacitor could be woven into clothing to power medical devices for people at home, or communications devices for soldiers in the field. The fiber could also be used as a space-saving power source and serve as "energy-carrying wires" in medical implants.
Yuan Chen, a professor of chemical engineering at NTU, led the new study, working with Dingshan Yu, Kunli Goh, Hong Wang, Li Wei, and Wenchao Jiang at NTU; Qiang Zhang at Tsinghua; and Liming Dai at CWRU. The scientists report their research in Nature Nanotechnology.
Dai, a professor of macromolecular science and engineering at Cleveland's CWRU and a co-author of the paper, explained that most supercapacitors have high power density but low energy density, which means they can charge quickly and give a boost of power, but don't last long. Conversely, batteries have high energy density and low power density, which means they can last a long time but do not deliver a large amount of energy quickly.