Select your localized edition:

Close ×

More Ways to Connect

Discover one of our 28 local entrepreneurial communities »

Be the first to know as we launch in new countries and markets around the globe.

Interested in bringing MIT Technology Review to your local market?

MIT Technology ReviewMIT Technology Review - logo

 

Unsupported browser: Your browser does not meet modern web standards. See how it scores »

{ action.text }

Carbon power: Twenty layers of carbon nanotubes are assembled on a polymer backing.

Nanotube Super-capacitors
A method for making electrodes doubles electrical storage capacity

Source: “Layer-by-Layer Assembly of All Carbon Nanotube Ultrathin Films for Electrochemical Applications”
Paula Hammond et al.
Journal of the American Chemical Society
131: 671-679

Results: MIT researchers have developed a new technique for making thin films of multi­walled carbon nanotubes. The materials have low electrical resistance and can store about 160 farads of electrical charge per gram–a capacitance more than twice that of other carbon nanotube films and an order of magnitude higher than that of conventional carbon materials.

Why it matters: Since the films can store large amounts of electrical charge and discharge it rapidly, they are promising materials for supercapacitors, long-lasting batterylike devices that charge up quickly. The way they’re made gives the researchers a great deal of control over their thickness and porosity, and thus over their electrical properties. That means the materials could be useful in diverse applications, including microbatteries for medical implants and flexible electrodes for electronics.

Methods: The researchers treated carbon nanotubes with either positively or negatively charged surface molecules, then put them into separate water suspensions. They dipped a substrate, such as a silicon wafer, alternately in the positive and negative nanotube solutions; the difference in charge created electrostatic attraction, causing the nanotubes to cling to one another without the need for chemical binders. (Previous nanotube films, which required such binders, did not have electrical properties as impressive as those displayed by a pure mat of nanotubes.) The researchers have now made nanotube films of varying thicknesses, released them from their substrates, and tested their electrical properties.

Next steps: The researchers will modify the nanotubes so that the materials can store even more charge. They are also developing faster assembly methods based on spraying rather than dipping.

0 comments about this story. Start the discussion »

Credit: Seung Woo Lee/ Journal of the American Chemical Society

Tagged: Energy, Materials

Reprints and Permissions | Send feedback to the editor

From the Archives

Close

Introducing MIT Technology Review Insider.

Already a Magazine subscriber?

You're automatically an Insider. It's easy to activate or upgrade your account.

Activate Your Account

Become an Insider

It's the new way to subscribe. Get even more of the tech news, research, and discoveries you crave.

Sign Up

Learn More

Find out why MIT Technology Review Insider is for you and explore your options.

Show Me