In a recent study published in Advanced Energy Materials, researchers from the Korea Institute of Science and Technology have developed a fiber-like electrode material using modified carbon nanotube fibers. This material offers high energy storage capacity and improved mechanical strength and conductivity.
The figure above shows a comparison of the mechanical and electrical conductivity property enhancement of functionalized carbon nanotube fiber compared to raw fiber, showing a 33-fold increase in electrochemical activity despite a clean surface with no active material. Image Credit: Korea Institute of Science and Technology
The latest wearable technology is revolutionizing healthcare and opening new career opportunities. These devices include Apple's Vision Pro and Samsung's Galaxy Ring.
Battery capacity is unavoidably constrained due to wearable devices' tiny size and light weight, which poses a technological challenge to integrating a range of tasks. Developing a lighter and more energy-efficient energy storage technique is vital for wearable technologies to fully achieve their imagined existence.
A collaborative research team led by Drs. Hyeonsu Jeong and Namdong Kim of the Center for Functional Composite Materials, Jeonbuk Branch, and Seungmin Kim of the Center for Carbon Fusion Materials have created an electrode material that resembles fibers and can store energy, according to a statement released by the Korea Institute of Science and Technology (KIST).
The fibers possess robustness, lightness, and exceptional flexibility, allowing for increased versatility in the design of wearable devices and facilitating their adaptation into diverse shapes and functionalities.
Due to their exceptional mechanical and electrical qualities, flexibility, and low weight, carbon nanotube fibers are a promising material for wearable technology. However, prior research has mostly used them as a current collector and coated their surface with active materials due to their tiny specific surface area and lack of electrochemical activity.
However, this method is not only unfeasible because of the high expense of extra materials and procedures, but it also increases the likelihood that the active material will separate from the fiber when it is used for an extended time or undergoes physical deformation.
The KIST research team created a fibrous electrode material with a large energy storage capacity to resolve this issue without using active components. The researchers spun powder-form carbon nanotubes into fibers after treating and altering them with acid to produce carbon nanotube fibers with good physical qualities and electrochemical activity.
The modified carbon nanotube fiber offers 33 times higher energy storage capacity, 3.3 times more mechanical strength, and more than 1.3 times better electrical conductivity than regular carbon nanotube fibers. Furthermore, wet spinning technology can be used to mass create the energy storage electrode material because it was made solely utilizing pure carbon nanotube fibers.
In tests using fiber-shaped supercapacitors, they maintained 95% of their performance after 5,000 bending tests and almost 100% of their performance when knotted. After being bent, folded, and cleaned, they also functioned well when woven into the wrist straps of digital watches using a blend of regular and carbon nanotube fibers.
Dr. Kim Seung-min explained, “We have confirmed that carbon nanotubes, which have recently started to attract attention again as a conductive material for secondary batteries, can be used in a much wider range of fields.”
Carbon nanotube fiber is a competitive field because we have the original technology and there is not much of a technology gap with advanced countries, we will continue our research to apply it as a core material for atypical energy storage.
Dr. Hyeon Su Jeong, Study Co-Researcher, Korea Institute of Science and Technology
Dr. Nam-dong Kim said, “We are currently conducting research to apply this technology to fiber-type batteries with higher energy density, going beyond supercapacitors.”
Journal Reference:
Yu, H., et al. (2023) Active Material‐Free Continuous Carbon Nanotube Fibers with Unprecedented Enhancement of Physicochemical Properties for Fiber‐Type Solid‐State Supercapacitors. Advanced Energy Materials. doi.org/10.1002/aenm.202303003