Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A simpler route to hollow carbon spheres

11.10.2013
Microporous walls and a huge surface area help nanoparticles to boost lithium-ion battery performance

Hollow carbon nanoparticles are strong, conduct electricity well and have a remarkably large surface area. They show promise in applications such as water filtration, hydrogen storage and battery electrodes - but commercial use would demand reliable, low-cost ways for their production.

Xu Li of Singapore's A*STAR Institute of Materials Research and Engineering and co-workers have developed a simple manufacturing technique that offers precise control over the size and shape of hollow carbon nanospheres1.

A current method for preparing these particles involves coating a hard template, such as silica nanoparticles, with a carbon-based material that can be fused into a shell using extreme heat. This is a laborious process, and etching away the template requires harsh chemicals. Heating hollow polystyrene nanospheres achieves similar results but offers poor control over the size and shape of the resulting carbon nanoparticles.

Li and co-workers combined a block copolymer called F127, consisting of poly(ethylene oxide) and poly(propylene oxide), with donut-shaped a-cyclodextrin molecules in water. After heating the mixture to 200°C, the molecules self-assembled into hollow nanoparticles with a 97.5% yield.

The water-repelling poly (propylene oxide) parts of the polymer stuck together to form hollow spheres, leaving poly (ethylene oxide) molecules dangling from the outside. The a-cyclodextrin rings then threaded onto these strands, packing around the outside of the sphere to form a stable shell. Using a higher proportion of F127 in the mix produced larger nanospheres, ranging from 200 to 400 nanometers in diameter. Heating these particles to 900°C in inert gases burned off the polymer to make hollow carbon nanoparticles.

The smallest nanospheres were 122 nanometers across and had 14 nanometer-thick walls dotted with tiny pores roughly 1 nanometer wide. Each gram of this material had a surface area of 317.5 square meters, which is greater than a tennis court.

The researchers used a slurry of particles to coat a copper foil and tested it as the anode in a lithium-ion battery. They found that the particles had a reversible charging capacity of 462 milliampere hours per gram - higher than graphite, a typical anode material - and could be recharged at least 75 times without significant loss of performance. The pores apparently allow lithium ions to migrate to the inside surfaces of the spheres. "Changing the porosity could improve the transport process for higher performance," suggests Li. The team now plans to incorporate metal and metal oxide materials into the hollow carbon nanospheres to further enhance their properties.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering

Associated links
http://www.research.a-star.edu.sg/research/6761
Journal information
Yang, Z.-C., Zhang, Y., Kong, J.-H., Wong, S. Y., Li, X. & Wang, J. Hollow carbon nanoparticles of tunable size and wall thickness by hydrothermal treatment of a-cyclodextrin templated by F127 block copolymers. Chemistry of Materials 25, 704−710 (2013).

A*STAR Research | Research asia research news
Further information:
http://www.a-star.edu.sg
http://www.researchsea.com

More articles from Power and Electrical Engineering:

nachricht Researchers use light to remotely control curvature of plastics
23.03.2017 | North Carolina State University

nachricht TU Graz researchers show that enzyme function inhibits battery ageing
21.03.2017 | Technische Universität Graz

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>