MIT researchers introduce nanotech battery
Nanotube ultracapacitors would store energy on
atomic level, providing what is said to be the first technologically significant
and economically viable alternative to conventional batteries in more than 200
Adapted from Press Release
Images of different types of carbon nanotubes. Carbon nanotubes are key to
MIT researchers' efforts to improve on an energy storage device called an
Just about everything that runs on batteries --
flashlights, cell phones, electric cars, missile-guidance systems -- would be
improved with a better energy supply. But traditional batteries haven't
progressed far beyond the basic design developed by Alessandro Volta in the 19th
Work at MIT's Laboratory for Electromagnetic and Electronic Systems (LEES) holds
out the promise of the first technologically significant and economically viable
alternative to conventional batteries in more than 200 years.
Joel E. Schindall, the Bernard Gordon Professor of Electrical Engineering and
Computer Science (EECS) and associate director of the Laboratory for
Electromagnetic and Electronic Systems; John G. Kassakian, EECS professor and
director of LEES; and Ph.D. candidate Riccardo Signorelli are using nanotube
structures to improve on an energy storage device called an ultracapacitor.
Capacitors store energy as an electrical field, making them more efficient than
standard batteries, which get their energy from chemical reactions.
Ultracapacitors are capacitor-based storage cells that provide quick, massive
bursts of instant energy. They are sometimes used in fuel-cell vehicles to
provide an extra burst for accelerating into traffic and climbing hills.
However, ultracapacitors need to be much larger than batteries to hold the same
The LEES invention would increase the storage capacity of existing commercial
ultracapacitors by storing electrical fields at the atomic level.
Although ultracapacitors have been around since the 1960s, they are relatively
expensive .Only recently were they manufactured in sufficient quantities to
become cost-competitive. Today you can find ultracapacitors in a range of
electronic devices, from computers to cars.
However, despite their inherent advantages -- a 10-year-plus lifetime,
indifference to temperature change, high immunity to shock and vibration and
high charging and discharging efficiency -- physical constraints on electrode
surface area and spacing have limited ultracapacitors to an energy storage
capacity around 25 times less than a similarly sized lithium-ion battery.
The LEES ultracapacitor has the capacity to overcome this energy limitation by
using vertically aligned, single-wall carbon nanotubes -- one thirty-thousandth
the diameter of a human hair and 100,000 times as long as they are wide.
How does it work?
Storage capacity in an ultracapacitor is proportional to the surface area of the
electrodes. Today's ultracapacitors use electrodes made of activated carbon,
which is extremely porous and therefore has a very large surface area. However,
the pores in the carbon are irregular in size and shape, which reduces
efficiency. The vertically aligned nanotubes in the LEES ultracapacitor have a
regular shape, and a size that is only several atomic diameters in width. The
result is a significantly more effective surface area, which equates to
significantly increased storage capacity.
The new nanotube-enhanced ultracapacitors could be made in any of the sizes
currently available and be produced using conventional technology.
"This configuration has the potential to maintain and even improve the high
performance characteristics of ultracapacitors while providing energy storage
densities comparable to batteries," Schindall said. "Nanotube-enhanced
ultracapacitors would combine the long life and high power characteristics of a
commercial ultracapacitor with the higher energy storage density normally
available only from a chemical battery."
This work was presented at the 15th International Seminar on Double Layer
Capacitors and Hybrid Energy Storage Devices in Deerfield Beach, Fla., in
The work has been funded in part by the MIT/Industry Consortium on Advanced
Automotive Electrical/Electronic Components and Systems and in part by a grant
from the Ford-MIT Alliance.
Source: MIT Press
Release, Feb. 8, 2006
Posted by "informed" to http://pub6.bravenet.com/forum/487525627/fetch/672697/
Feb 10, 06 - 12:31 AM
I opened this page on Sterling's PES network and was surprisingly amazed. You
can check this out at the following link: /2006/02/09/9600232_MIT_Battery/
I am excited because after looking at hundreds of up-coming new technologies
over ten years ago, I narrowed the choices down to a few that I thought had
promise and ultra-capacitors on a micro scale was one of them. Of course, back
then, MEMS were the "in" technology and Bucky balls and nano-tubes
were still in the discovery stage. My idea was to mass produce these micro
capacitors on silicon wafers. With the current 300mm wafers you can cut a eight
inch square from the middle and end up with 64 square inches per wafer (8"
X 8" = 64). These wafers can be stacked 16 wafers per inch high, so the
bottom line is a package that is 8" X 8" X 6 1/4 high = 100 wafers, =
6,400 square inches.
Now that the new 450mm wafers will be coming online soon, you can see that
10,000 square inches can be produced to match the size of today's current car
battery's. Of course this figure may be cut in half to 5,000 square inches if a
1/16th space is required in between wafers to allow for cooling which I believe
will be the case. The wafers are connected with copper (or other more suitable
material) rods drilled into the corners. The end result is a block containing
millions of nano ultra-capacitors in a size similar to today's batteryies.
Of course I am leaving out many details like how to scale up this stored energy
to a useable power source but I see these same issues being resolved in today's
current electronics. Keep in mind that this block of capacitors only stores
energy put into it and does not produce its own energy. I have bounced around
several ideas for producing the energy to be stored in this block and my current
favorite are these micro turbines being produced in Germany for large RC
aircraft. These little turbines not much bigger than the size of your hand, can
produce 100 pounds of thrust and I believe can power a small generator at a
constant speed continuously, thus keeping the capacitor block charged. So there
is the idea in a nut-shell. I would be interested in hearing anyone's thoughts
Page composed by Sterling
D. Allan Feb. 25, 2006
Last updated December 24, 2014