Fibrous Carbon Nanotubes Can Be Woven Into High-Performance "Energy Clothes".

< p > if the new products of Google eyewear (Google Glass) and the upcoming apple iWatch smart watches are coming soon, wearable electronic products will probably trigger the next wave of new technology. In order to solve the problem of power supply for such products, researchers from Fudan University in Shanghai, China, have prepared for the first time a fiber based lithium ion battery based on carbon nanotubes (CNT), which can be flexibly woven into high-performance flexible energy textiles. The research is published in the latest issue of nano express. < /p >
< p > from head display to biomedical monitoring, wearable electronic products can provide many advanced functions. They require very high batteries. They are not only small in size and light in weight, but also have the powerful energy needed to satisfy many functions of the equipment. Therefore, the biggest technical bottleneck of wearable electronic products is the battery. < /p >
< p > according to the physicist tissue network May 27th, the new research and design of carbon nanotube (CNT) composite yarns can be tightly wound into cotton fibers to create high-performance lithium-ion batteries. The diameter of the fiber is about 1 millimeters, it can be woven into flexible fabric or cloth, and is compatible with flexible wearable electronic equipment. < /p >
Weng Wei, who took part in the research, said: "it is very necessary that this power supply can be directly integrated seamlessly into wearable electronic products." P Because it needs to be woven into clothing flexibly, the fibrous power supply is ideal. Although this is the first carbon nanotube like lithium ion battery, it exhibits excellent electrochemical performance, including high energy density up to 750 billion watts / square centimeter, and after 100 cycles, the battery has a capacity of 87%. < /p >
One of the biggest challenges in designing P based lithium ion batteries is the widely known problem of silicon expansion. Chemical reactions will occur during charging / discharging processes, and the volume of silicon will undergo a great change of 300%. To adapt to this situation, the researchers introduced carbon nanotube into a composite CNT/ silicon yarn anode. The carbon nanotube effectively cushioned silicon < a href= "http://www.91se91.com/news/index_c.asp" > volume change < /a >, and solidified it firmly. Without such a hybrid structure, the expansion of silicon will cause it to peel off and lead to battery damage. < /p >
< p > for the cathode materials, researchers use carbon nanotubes and lithium manganate. The advantages are high stability, high working voltage and low cost. By separating the CNT based yarn from the anode and cathode separated from the gel electrolyte, the lithium ion battery can be woven into a flexible < a href= "http://www.91se91.com/news/index_c.asp" > fabric < /a >. < /p >
Before P, researchers tried to make super a href= "http://www.91se91.com/news/index_c.asp" > capacitor fiber < /a >, but because of the difficulty in manufacturing lithium ion battery fiber, much attention has not been paid to it. However, lithium-ion batteries have certain advantages, such as higher energy density and lower self discharge losses. Compared with supercapacitors, they offer better choices for general wearable electronic devices. The researchers explained that in this regard, the current work has been improved based on previous studies, but there is still room for further improvement. < /p >
"P," the researchers said, "in 2012, the lithium ion battery used copper wire as a skeleton with a cable like shape. The result is great, but because the battery has large diameter, liquid electrolyte and heavy, it may not be suitable for weaving energy textiles. Now the carbon nanotube fiber is used as its skeleton, and its density is close to that of copper 1/9, and the gel electrolyte is used to ensure safety. In addition, the anodes and cathodes of the composite yarns are made of carbon nanotube fibers and active materials with a diameter of 100 m, which are only anodes 1/10 in the cable batteries. Therefore, the fiber like batteries are compatible with polymer fibers used for making garments and achieve high performance batteries. < /p >
< p > in the future, researchers plan to further improve this fiber battery in various fields. The researchers said: "first, improve performance, such as capacity and cycle life; secondly, scale production; third, other functions will be combined, such as stretching, discoloration and self power supply." (China Science and Technology Net - Science and technology daily) < /p >