Penny-Sized Nuclear Batteries Developed 444
pickens writes "Nuclear batteries that produce energy from the decay of radioisotopes are an attractive proposition for many applications because the isotopes that power them can provide a useful amount of current for hundreds of years at power densities a million times as high as standard batteries. Nuclear batteries have been used for military and aerospace applications for years, their large size has limited their general usage. But now a research team at the University of Missouri has developed a nuclear battery the size of a penny that could be used to power micro- and nano-electromechanical systems. The researchers' innovation is not only in the battery's size, but also that the batteries use a liquid semiconductor rather than a solid semiconductor. 'The critical part of using a radioactive battery is that when you harvest the energy, part of the radiation energy can damage the lattice structure of the solid semiconductor,' says Jae Wan Kwon. 'By using a liquid semiconductor, we believe we can minimize that problem.' The batteries are safe under normal operating conditions. 'People hear the word "nuclear" and think of something very dangerous,' says Kwon. 'However, nuclear power sources have already been safely powering a variety of devices, such as pacemakers, space satellites, and underwater systems.'"
Re:ohhhhh... (Score:5, Informative)
Iran has crude oil. What they *don't* have is gasoline...fuel oil...asphalt...and so on. Iran has very little in the way of refining capability (it didn't help that a large chunk of their refineries got blown up in the Iraq-Iran war). In fact, one of the sanctions that's been discussed for Iran is cutting off their gasoline supply.
How much voltage/current? (Score:5, Informative)
Re:Power density or energy? (Score:3, Informative)
TFA mentions nothing about the actual power these things can put out.
A power source that lasts forever is suddenly not very useful if it only delivers a few milliwatts. I can see its uses, but it won't be replacing lithium ion batteries in phones and laptops any time soon.
Re:Pacemakers? (Score:4, Informative)
Come on now, Iron Man isn't real!
That wasn't nuclear power, that was an Arc Reactor. Which is short for Story Arc Plot Hole Reactor. It runs on the writer's need for an infinite power source.
Re:Cars??? (Score:1, Informative)
"Nucular" is a term made popular by an earlier President of the US, one James Earl Carter, Jr.
Rated in Nanoamps (Score:3, Informative)
It would be great to replace the power packs of everything with them, but they are currently rated in nanoamps of output and microvolts of potential. Scaling them up (and making them cost less than $1 million for a AA cell) is the challenge and its a big one that will take a lot of work.
Shielding isn't a big problem incidentally.From other articles one of the popular nuclear sources is tritium which is used on gunsights and stairwell markings. Half life is pretty short and shielding level required is skin (i.e. don't eat it or breath it).
Re:How much voltage/current? (Score:4, Informative)
According to http://nextbigfuture.com/2009/10/liquid-nuclear-battery-that-could-have.html, which quotes the published paper, the battery provides 16.2 nW, has open-circuit voltage of 899 mV, and short-circuit current of 107.4 nA. When they talk about micro- and nano-mechanical applications, they're not kidding. It would take a stack of 61,728,395 of them to provide 1 watt.
WRONG (Score:5, Informative)
Something that produces energy from the decay of radioisotopes is called a Radioisotope Thermoelectric Generator (RTG) whereas a battery is an array of electrochemical cells for electricity storage.
You didn't read the article.
The batteries use Sulfur-35 which is a beta emitter. Aka, electrons. They do not use thermocouples at all.
Read about it here: http://en.wikipedia.org/wiki/Betavoltaics [wikipedia.org]
Re:This is NOT a battery, it's a RTG (Score:3, Informative)
"So, make an inventory of the smoke detectors you own. If the total is above 3 then you are in possession of enough nuclear material that would require you to get a license from the NRC. If you don't have a license from the NRC and own more than 3 smoke detectors you are likely in possession of an illegal amount of barium and could be flagged as an enemy combative and thanks to George W. Bush enemy combative have no right to any legal representation and can be summarily executed or detained for an indefinite amount of time without even informing anyone that they took you into custody."
First of all, don't most smoke detectors use Americium, not Barium? Secondly, from what I can find, the NRC doesn't required a license unless you have more than 10 microcuries (for Barium), and most smoke detectors use only 1.
Article Information (Score:1, Informative)
The actual paper is "Radioisotope microbattery based on liquid semiconductor," by T. Wacharasindhu, J. W. Kwon, D. E. Meier, and J. D. Robertson in "Applied Physics Letters" (Appl. Phys. Lett. 95, 014103 (2009)). DOI: 10.1063/1.3160542
From the conclusion of the article:
Re:Mini-RTG (Score:3, Informative)
It is not an RTG. RTG devices run pretty hot - thermal, you get it.
What these devices do is output an incredibly small amount of electricity from the actual radioactive decay of materials. Incredibly small. Microwatts.
They are used in pacemakers and the like because of extremely low power requirements - less than a watch - and the need for a stable power source that will last years and years.
It might be possible to stack up 100 of these to power a single LED. That is the level of output from these devices. And they aren't cheap.
Re:Would never be in consumer applications (Score:1, Informative)
Radium/Tritium is not used for watch dials anymore. Decades ago it has been replaced by superluminova which is not radioactive.
Re:So what do you think about the type of plants (Score:4, Informative)
Re:ohhhhh... (Score:4, Informative)
From TFA:
"To provide enough power, we need certain methods with high energy density," said Jae Kwon, assistant professor of electrical and computer engineering at MU. "The radioisotope battery can provide power density that is six orders of magnitude higher than chemical batteries."
Power density.
Re:So what do you think about the type of plants (Score:3, Informative)
First off, you can use either light or heavy water reactor to make plutonium, it makes little difference except that a short cycle (typical but not necessary of heavy water reactors) makes better plutonium.
Enrichment is necessary for light water but not heavy water, although it can be economically beneficial for a heavy water reactor.
Heavy water reactors are no bigger, except that the capital costs makes large ones more viable.
The biggest reactors in the world are light water.
Also, the first reactors did not use heavy water, they were graphite moderated.