Featured Research

from universities, journals, and other organizations

Tiny Atomic Battery Could Run For Decades Unattended

Date:
October 18, 2002
Source:
Cornell University
Summary:
While electronic circuits and nanomachines grow ever smaller, batteries to power them remain huge by comparison, as well as short-lived. But now Cornell University researchers have built a microscopic device that could supply power for decades to remote sensors or implantable medical devices by drawing energy from a radioactive isotope.

ITHACA, N.Y. -- While electronic circuits and nanomachines grow ever smaller, batteries to power them remain huge by comparison, as well as short-lived. But now Cornell University researchers have built a microscopic device that could supply power for decades to remote sensors or implantable medical devices by drawing energy from a radioactive isotope.

The device converts the energy stored in the radioactive material directly into motion. It could directly move the parts of a tiny machine or could generate electricity in a form more useful for many circuits than has been possible with earlier devices. This new approach creates a high-impedance source (the factor that determines the amplitude of the current) better suited to power many types of circuits, says Amil Lal, Cornell assistant professor of electrical and computer engineering.

Lal and Cornell doctoral candidate Hui Li described a prototype of the device at a U.S. Department of Defense meeting of Defense Advanced Research Projects Agency (DARPA) investigators in Detroit in August. The prototype is the first MEMS (micro-electromechanical systems) version of a larger device that Lal designed and built while a member of the faculty at the University of Wisconsin, Madison, working with nuclear engineering professors James Blanchard and Douglas Henderson.

The prototype device uses a copper cantilever 2 centimeters long. Future nanofabricated versions could be smaller than one cubic millimeter.

The prototype is made up of a copper strip 1 millimeter wide, 2 centimeters long and 60 micrometers (millionths of a meter) thick that is cantilevered above a thin film of radioactive nickel-63 (an isotope of nickel with a different number of neutrons from the common form). As the isotope decays, it emits beta particles (electrons). Radioactive materials can emit beta particles, alpha particles or gamma rays, the last two of which can carry enough energy to be hazardous. Lal has chosen only isotopes that emit beta particles, whose energy is small enough not to penetrate skin, to be used in his device.

The emitted electrons collect on the copper strip, building a negative charge, while the isotope film, losing electrons, becomes positively charged. The attraction between positive and negative bends the rod down. When the rod gets close enough to the isotope, a current flows, equalizing the charge. The rod springs up, and the process repeats. The principle is much like that underlying an electric doorbell, in which a moving bar alternately makes and breaks the electric circuit supplying an electromagnet that moves the bar.

Radioactive isotopes can continue to release energy over periods ranging from weeks to decades. The half-life of nickel-63, for example, is over 100 years, and Lal says a battery using this isotope might continue to supply useful energy for at least half that time. (The half-life is the time it takes for half the atoms in an element to decay.) Other isotopes offer varying combinations of energy level versus lifetime. And unlike chemical batteries, the devices will work in a very wide range of temperatures. Possible applications include sensors to monitor the condition of missiles stored in sealed containers, battlefield sensors that must be concealed and left unattended for long periods, and medical devices implanted inside the body.

The moving cantilever can directly actuate a linear device or can move a cam or ratcheted wheel to produce rotary motion. A magnetized material attached to the rod can generate electricity as it moves through a coil. Lal also has built versions of the device in which the cantilever is made of a piezoelectric material that generates electricity when deformed, releasing a pulse of current as the rod snaps up. This also generates a radio-frequency pulse that could be used to transmit information. Alternatively, Lal suggests, the electrical pulse could drive a light-emitting diode to generate an optical signal.

In addition to powering other devices, the tiny cantilevers could be used as stand-alone sensors, Lal says. The devices ordinarily operate in a vacuum. But the sensors might be developed to detect the presence or absence of particular gases, since introducing a gas to the device changes the flow of current between the rod and the base, in turn changing the period or amplitude of the oscillation. Temperature and pressure changes also can be detected.

Lal, Li and Cornell doctoral candidate Hang Guo are now building and testing practical sensors and power supplies based on the concept. The prototype shown in August was gigantic by comparison with the latest versions, Lal says. An entire device, including a vacuum enclosure, could be made to fit in less than one cubic millimeter, he says.


Story Source:

The above story is based on materials provided by Cornell University. Note: Materials may be edited for content and length.


Cite This Page:

Cornell University. "Tiny Atomic Battery Could Run For Decades Unattended." ScienceDaily. ScienceDaily, 18 October 2002. <www.sciencedaily.com/releases/2002/10/021018080122.htm>.
Cornell University. (2002, October 18). Tiny Atomic Battery Could Run For Decades Unattended. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2002/10/021018080122.htm
Cornell University. "Tiny Atomic Battery Could Run For Decades Unattended." ScienceDaily. www.sciencedaily.com/releases/2002/10/021018080122.htm (accessed July 23, 2014).

Share This




More Matter & Energy News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Government Approves East Coast Oil Exploration

Government Approves East Coast Oil Exploration

AP (July 18, 2014) The Obama administration approved the use of sonic cannons to discover deposits under the ocean floor by shooting sound waves 100 times louder than a jet engine through waters shared by endangered whales and turtles. (July 18) Video provided by AP
Powered by NewsLook.com
Sunken German U-Boat Clearly Visible For First Time

Sunken German U-Boat Clearly Visible For First Time

Newsy (July 18, 2014) The wreckage of the German submarine U-166 has become clearly visible for the first time since it was discovered in 2001. Video provided by Newsy
Powered by NewsLook.com
Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Reuters - US Online Video (July 17, 2014) President Barak Obama stopped by at a lunch counter in Delaware before making remarks about boosting the nation's infrastructure. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

TheStreet (July 16, 2014) Oil Futures are bouncing back after tumbling below $100 a barrel for the first time since May yesterday. Jeff Grossman is the president of BRG Brokerage and trades at the NYMEX. Grossman tells TheStreet the Middle East is always a concern for oil traders. Oil prices were pushed down in recent weeks on Libya increasing its production. Supply disruptions in Iraq fading also contributed to prices falling. News from China's economic front showing a growth for the second quarter also calmed fears on its slowdown. Jeff Grossman talks to TheStreet's Susannah Lee on this and more on the Energy Department's Energy Information Administration (EIA) report. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins