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"Spin Battery" Effect Discovered
An anonymous reader writes "Researchers at the University of Miami and at the Universities of Tokyo and Tohoku, in Japan, have discovered a spin battery effect: the ability to store energy into the magnetic spin of a material and to later extract that energy as electricity, without a chemical reaction. The researchers have built an actual device to demonstrate the effect that has a diameter about that of a human hair. This is a potentially game-changing discovery that could affect battery and other technologies. Quoting: Although the actual device... cannot even light up an LED..., the energy that might be stored in this way could potentially run a car for miles. The possibilities are endless, Barnes said.'"
In THIS house, we obey the laws of thermodynamics. So you create a magnetic field, okay. Great. What's to prevent everything that's metallic in the area from moving around it, inducing current in it, and converting it into useless thermal energy? In other words -- what's preventing the battery from discharging? It might be good for a really high-capacity capacitor, but a battery? Batteries are long term.
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If this does prove to be useful for batteries, would it eliminate issues related to battery memory?
It appears current rechargeable batteries "age" due to chemical reactions even if not used. Even more so due to repeated charge cycles.
With no chemical reactions in play, does this mean people won't be forced to upgrade their phones simply because their battery is all but dead?
Although the actual device... cannot even light up an LED..., the energy that might be stored in this way could potentially run a car for miles.
This is one of the least informative lines ever included in a tech summary.
Any energy storing tech that's worth it's salt can potentially run a car for miles. It's a question of efficiency and cost. I can potentially power a car for miles with twisted up rubberbands if I want to, but that isn't a breakthrough in the field.
And of course "miles" tells nothing. Powering a car 3-5 miles is next to worthless. If they said 10's of miles we would know this had the potential to replace current tech or at least come close. If they said 100's of miles we would be facing a revolutionary improvement.
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... and not all of it from the magnets themselves.
At least for the proof of concept stage, they might want to make a light source that consumes significantly less juice than an LED, and has a greater tolerance for fluctuation.
From Wikipedia:
"LEDs must be supplied with the voltage above the threshold and a current below the rating. This can involve series resistors or current-regulated power supplies." http://en.wikipedia.org/wiki/Led#Disadvantages
Using an LED as an example of what this tiny power souce can't power seems futile at this point.
That we're talking about _spin_ here, as in a property of subatomic particles corresponding to an 'intrinsic' angular momentum, not as in something that's physically 'spinning'. Electrons spin +1/2 or -1/2 and that's it. They can't stop. The energy here is being stored in the form of the _orientations_ of these spins, not the spin itself. What's keeping them that way is conservation of spin. Which is analogous to conservation of angular momentum. (Bound) Electrons can't change their spin state spontaneously. Which is why stuff which is magnetized stays that way for a long time. It's also the reason for phosphorescence. While I think what they've done here is undeniably pretty cool, in turning spin-state transitions into electricity directly, it's probably not going to create any real competition for conventional batteries, for fairly simple reasons. Batteries store electricity in the form of chemical redox states, which means adding/removing electrons from atoms/ions. The energy differences between spin states are typically an order of magnitude smaller than the energy difference between redox states.
surely?
How can you be sure when they didn't post anything about the energy density? (Maybe there is some info in the original article, but I don't have access to the journal.
Correct, just like a spiders web strand is stronger for its size than steel. I predict we will be building skyscrapers out of spider web about the same time as this new technology matures.
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