Do you know Tritium ? It is an isotope of hydrogen (H rated 3), ie, an atom with neutrons more or less in the nucleus - two more neutrons in this case.
The particularity of tritium is that it is a radioisotope, a word which is not afraid to say it is radioactive. Oh, nothing to do with uranium-235, do not worry. It degrades slowly by emitting beta-minus decay radiation - in other words, it emits electrons.
Moreover these electrons can recover in semiconductors. Result ? This makes an electric current.
Here is beta-voltaic system.
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| principle of Tritium battery |
It's been a while since we worked on this : the principle was discovered fifty years ago, and they are already feeding of satellites as per their long-term life, it has been used also for cardiac stimulators. Because the strength of this power is that his life is closely linked to the degradation of the selected element : electricity production is continuous, decreasing gradually until complete degradation.
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| from http://www.betavoltaic.co.uk |
It is reasonable to expect that a beta-voltaic battery tritium produces electricity for thirty years.
Today, following research of the U.S. Air Force was announced in the coming years beta-voltaic cells for cell phones or laptops.
Some will worry about bringing sources radiating into their lives. Hopefully, tritium is kind enough not to issue any other radiation than beta emission, which are not harmful and easily controllable (single aluminum foil easily stop them, as well as human skin). Besides, you may have some already in your environment : tritium is commonly used in the manufacture of luminescent watch (it replaced radium for this use, which emitted more gamma carcinogen radiation).
Another advantage : once emptied, the battery would contain no more radioactive element and would be inert and harmless : the degradation of tritium produces helium 3, perfectly stable. In fact, it would even be much cleaner than the current batteries containing heavy metals.
Then, is betavoltaic battery the panacea for computers, without being to be charged until 2050 ?
> not quite sure: the production of tritium is not without issues.
The size of the tritium atom (remember that hydrogen is the smallest of all atoms) makes it very difficult to store: it has a tendency to penetrate most materials. Also, emission is divided by two every decaying period (12.32 years), which means the battery must be over-sized at the beginning of its life in order to be still usable at its end of life.
Still, this line of research appears very promising, the main issue being miniaturizing sufficiently the gaz container to fit in a laptop.
For instance, porous silicium and 3D shaped silicium will help to overgo these limitations
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| Nanowatt batteries, lasting 20 years. Credit from http://www.citylabs.net |
More about betavoltaic :
http://peswiki.com/index.php/PowerPedia:BetaVoltaic
http://www.livescience.com/technology/091209-nuclear-batteries.html
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