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 Linear potentiometer LRW2/3 - Maximum precision with many measuring points
17.05.2017 | WayCon Positionsmesstechnik GmbH

nachricht First flat lens for immersion microscope provides alternative to centuries-old technique
17.05.2017 | Harvard John A. Paulson School of Engineering and Applied Sciences

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: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

 
Latest News

Zap! Graphene is bad news for bacteria

23.05.2017 | Life Sciences

Medical gamma-ray camera is now palm-sized

23.05.2017 | Medical Engineering

Discovery of an alga's 'dictionary of genes' could lead to advances in biofuels, medicine

23.05.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>