Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tiny atomic battery developed at Cornell could run for decades unattended, powering sensors or machines

18.10.2002


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


Beta particles (electrons) released from a thin film of radioactive material are absorbed by the cantilever, giving it a negative charge. The cantilever is pulled down toward the positively charged film until it is near enough for a current to flow and equalize the charge. The cantilever springs back up, and the process repeats.
Copyright © Cornell University


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 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.

Bill Steele | EurekAlert!
Further information:
http://www.news.cornell.edu/

More articles from Power and Electrical Engineering:

nachricht A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes
20.07.2018 | Science China Press

nachricht Future electronic components to be printed like newspapers
20.07.2018 | Purdue University

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: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>