Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Battery Design Gets Boost from Aligned Carbon Nanotubes

07.08.2013
Researchers at North Carolina State University have created a new flexible nano-scaffold for rechargeable lithium ion batteries that could help make cell phone and electric car batteries last longer.

The research, published online in Advanced Materials, shows the potential of manufactured sheets of aligned carbon nanotubes coated with silicon, a material with a much higher energy storage capacity than the graphite composites typically used in lithium ion batteries.


A sheet of aligned carbon nanotubes is rolled on a cylinder. Copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.

“Putting silicon into batteries can produce a huge increase in capacity—10 times greater,” said Dr. Philip Bradford, assistant professor of textile engineering, chemistry and science at NC State. “But adding silicon can also create 10 times the problems.”

One significant challenge in using silicon is that it swells as lithium ion batteries discharge. As the batteries cycle, silicon can break off from the electrode and float around (known as pulverization) instead of staying in place, making batteries less stable.

When the silicon-coated carbon nanotubes were aligned in one direction like a layer of drinking straws laid end to end, the structure allowed for controlled expansion so that the silicon is less prone to pulverization, said Xiangwu Zhang, associate professor of textile engineering, chemistry and science at NC State.

“There’s a huge demand for batteries for cell phones and electric vehicles, which need higher energy capacity for longer driving distances between charges,” Zhang said. “We believe this carbon nanotube scaffolding potentially has the ability to change the industry, although technical aspects will have to be worked out. The manufacturing process we’re using is scalable and could work well in commercial production.”

The research was supported by the Donors to the American Chemical Society Petroleum Research Fund.

Note to editors: An abstract of the paper follows.

“Aligned Carbon Nanotube-Silicon Sheets: A Novel Nano-architecture for Flexible Lithium Ion Battery Electrodes”

Published: Online Aug. 1 in Advanced Materials

Authors: Kun Fu, Ozkan Yildiz, Hardik Bhanushali, Yongxin Wang, Kelly Stano, Leigang Xue, Ziangwu Zhang, and Philip D. Bradford

Abstract: In the pursuit of high performance lithium ion batteries (LIBs), significant effort has been expended to explore high performance cathode and anode materials. Silicon has the greatest lithium storage capacity per unit mass, and is therefore one of the most promising potential candidates to replace graphite as the anode material in future generations of batteries. The main challenge in utilizing silicon comes from the structural failure induced by its large volume change (>300%) during electrochemical cycling, leading to capacity loss. New designs, in which silicon and carbon can act in a mutually beneficial way, so that silicon can fully contribute to the capacity while maintaining cyclic stability, are needed. With this in mind, this communication describes novel, binder-free, thin sheet anodes for LIBs using aligned carbon nanotube (CNT) based silicon films which were processed in a way that is conducive to future commercial production. The horizontal super-aligned CNT sheets provided high surface area and a porous structure to facilitate both the uniform chemical vapor deposition of silicon during fabrication and the electrochemical kinetics between the silicon and the electrolyte during use. The CNT-based silicon composite sheets had both high specific energy capacity and stable cycle performance. This work also revealed an interesting new mechanism of deformation for silicon coated CNT structures after electrochemical cycling. A spring-like deformation behavior of the aligned CNTs helped to explain the electrochemical stability of the crystalline silicon coatings. These findings will guide future work to optimize this unique nano-architecture for further increases in energy density and stability. This aligned CNT scaffold design may be extended to other anode and cathode materials utilized in thin and flexible LIBs.

Dr. Philip Bradford | EurekAlert!
Further information:
http://www.ncsu.edu

More articles from Materials Sciences:

nachricht Research finds new molecular structures in boron-based nanoclusters
13.07.2018 | Brown University

nachricht 3D-Printing: Support structures to prevent vibrations in post-processing of thin-walled parts
12.07.2018 | Fraunhofer-Institut für Produktionstechnologie IPT

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Subaru Telescope helps pinpoint origin of ultra-high energy neutrino

16.07.2018 | Physics and Astronomy

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides

16.07.2018 | Life Sciences

New research calculates capacity of North American forests to sequester carbon

16.07.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>