Carbon Nanotubes Improve Fuel Cells

Mar 27, 2008 By Laura Mgrdichian feature

A group of scientists has created a new, improved fuel-cell electrode that is very lightweight and thin. Composed of a network of single-walled carbon nanotubes, the electrode functions nearly as well as conventional electrodes but renders the entire fuel cell much lighter. The research is an important step toward lightweight power supplies, which are becoming necessary as electronic devices get ever smaller and more streamlined.

The research was performed by scientists from the Max Planck Institute for Solid State Research and the University of Darmstadt, both in Germany, and is described in the March 5, 2008, online edition of Applied Physics Letters.

“Fuel cells that are light and small have been proposed as energy conversion devices in various portable appliances, such as cell phones, cameras, and notebook computers. Since the space and weight of the devices are key requirements, the energy density they provide should be maximized,” said the paper's corresponding scientist, Martti Kaempgen, now a researcher at the University of California at Los Angeles,* to PhysOrg.com. “In this context, carbon nanotubes have an advantage over other materials.”

The nanotube networks form the fuel cell's gas diffusion electrode, a layer of a porous material that allows gas and water vapor to pass through to the catalyst layer. In the catalyst layer, which typically consists of platinum particles, the protons and electrons of the gaseous reactant material—i.e. the fuel cell's fuel—are separated, and the electrons become electricity.

Earlier approaches utilizing carbon nanotubes in fuel cells have not taken full advantage of this material, only used as an additive to improve some of the properties of conventional electrode materials. But, until now, carbon nanotubes haven't been recognized as having the potential to replace the entire electrode.

Typically, carbon without any crystalline structure, known as amorphous carbon, is used in fuel cells because of its large surface area and porosity. Networks made of pure, single-walled carbon nanotubes boast the same properties, but weigh far less. They are ten times thinner and lighter than traditional electrodes. In addition, the long, thin shapes of the nanotubes give them a high conductivity—more than one thousand times larger than that of amorphous carbon. This is high enough that the current collector, another component of fuel cells, can be replaced as well.

The ability of a single material to perform several essential functions in a fuel cell leads to a much simpler fuel cell architecture.

The researchers tested the new electrode inside a home-made fuel cell using both hydrogen and oxygen gases as the fuel.

Though the overall performance of the electrode isn't all that impressive, “It is still comparable to conventional amorphous carbon types,” says Kaempgen. “And the lower performance is likely due to the preparation of the catalyst, which has yet to be optimized.”

*Kaempgen participated in this research while a Ph.D. candidate at the Max Planck Institute.

Citation: Applied Physics Letters 92, 094103 (2008)

Copyright 2008 PhysOrg.com.
All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.

Explore further: New absorber will lead to better biosensors

add to favorites email to friend print save as pdf

Related Stories

Smallest possible diamonds form ultra-thin nanothreads

Sep 21, 2014

For the first time, scientists have discovered how to produce ultra-thin "diamond nanothreads" that promise extraordinary properties, including strength and stiffness greater than that of today's strongest ...

Chemists develop novel catalyst with two functions

Jul 09, 2014

Chemists at the Ruhr-Universität Bochum have made a decisive step towards more cost-efficient regenerative fuel cells and rechargeable metal-air batteries. They developed a new type of catalyst on the basis ...

Recommended for you

New absorber will lead to better biosensors

9 hours ago

Biological sensors, or biosensors, are like technological canaries in the coalmine. By converting a biological response into an optical or electrical signal, they can alert us to dangers in our external and internal environments. ...

Ultrafast remote switching of light emission

Sep 30, 2014

Researchers from Eindhoven University of Technology can now for the first time remotely control a miniature light source at timescales of 200 trillionth of a second. They published the results on Sept. 2014 ...

Nanotube cathode beats large, pricey laser

Sep 30, 2014

Scientists are a step closer to building an intense electron beam source without a laser. Using the High-Brightness Electron Source Lab at DOE's Fermi National Accelerator Laboratory, a team led by scientist ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

paulo
2 / 5 (6) Mar 27, 2008
They just want to keep selling fuel.

Batteries can be recharged for free from the Sun.
x-15
2.8 / 5 (4) Mar 28, 2008
I second that. I can see a time in the future where progress will stop in the development of batteries and solar panels purely to keep us buying fuel. I don't like where this fuel cell stuff is going.
earls
3.8 / 5 (4) Mar 29, 2008
Energy Density by Mass (MJ/kg)

Lithium ion battery with nanowires: ~2.63

Gasoline: 46.9

It's all very simple.

Sure, as mentioned, free energy is available anywhere. It's storing it efficiently and effectively that is the main hurdle.
paulo
3 / 5 (4) Mar 30, 2008
yeah, but batteries are re-usable.

once you burn gasoline it's gone.

and making hydrogen is a very lossy way to store energy.
AgentG
1 / 5 (1) Apr 04, 2008
The only viable energy options are nuclear or solar, combined with energy storage. We need to focus all our resources on cheaper and lighter energy storage. Once this happens, we will have won the game.