Elastic wire-shaped lithium ion batteries with high electrochemical performance
Flexible smartphones, “intelligent” bracelets, glasses with a built-in computer: for these trends to take off, we need suitable power systems. Chinese scientists have now developed a wire-shaped lithium ion battery that contains electrodes consisting of two composite yarns made of carbon nanotubes and lithium titanium oxide or lithium manganese oxide. As the researchers report in the journal Angewandte Chemie, they were able to weave their batteries into light, flexible, elastic, and safe textile batteries with a high energy density.
Previous methods for producing wire-shaped electrochemical supercapacitors by twisting two fiber electrodes together resulted in systems with inferior performance that prevented them from being brought to the market. Lithium ion batteries can attain significantly higher energy density, but have not previously been produced in wire form.
In addition to other barriers, the safety problems associated with lithium ion batteries really come into play. The source of the safety problem is dendritic lithium, which can form during over-charging, “growing” out of the anode and causing a short circuit. This can cause the battery to ignite. This seems especially critical for wire-shaped batteries that can be stretched, twisted, and bent during use.
A team led by Huisheng Peng from Fudan University in Shanghai has now succeeded in producing wire-shaped lithium ion batteries that have a high energy density and are also safe. Their success results from the special structure as well as the materials used. The anode and cathode are two fibers made of parallel multiwalled carbon nanotubes that contain either lithium titanium oxide (LTO) or lithium manganese oxide (LMO) particles, respectively.
When the battery is charging, lithium ions are transferred from the LMO lattice to the electrolyte and then into the LTO lattice of the anode. The reverse process occurs as the battery is being discharged. Because the Li insertion takes place at ~1.5 V (vs. Li/Li+) for the applied LTO composite electrode, the chance of short circuit caused by dendritic lithium would be small and therefore the batteries are safe.
The parallel arrangements of continuous carbon nanotubes hold the nanoparticles; they are also efficient pathways for charge transport and serve as current collectors. The two electrode yarns are arranged in parallel, separated by a layer of insulator, and enclosed in a heat-shrinkable tube.
To make the wires elastic, they can be wrapped around an elastic fiber such as polydimethylsiloxane and coated with a thin-layer gel electrolyte. Neither repeated stretching to twice its original length nor thousands of deformation cycles reduces the battery capacity.
The wire-shaped batteries can be spun into long fibers and woven into a fabric that can be incorporated into textiles.
About the Author
Dr. Huisheng Peng is a Professor of Department of Macromolecular Science and Laboratory of Advanced Materials at Fudan University. His research centers on functional composite materials and their energy applications. Peng and co-workers created aligned carbon nanotube/polymer composites and developed novel wire-shaped solar cells, Li-ion batteries, and supercapacitors.
Author: Huisheng Peng, Fudan University, Shanghai (China), http://www.polymer.fudan.edu.cn/polymer/research/Penghs/member_en.htm
Title: Elastic and Wearable Wire-Shaped Lithium-Ion Battery with High Electrochemical Performance
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201402388
Huisheng Peng | Angewandte Chemie
The birth of a new protein
20.10.2017 | University of Arizona
Building New Moss Factories
20.10.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research