Degraded Electrodes Observed In Aging Batteries

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Degraded Electrodes Observed In Aging Batteries

Posted by timothy on Wednesday October 20, 2010 @12:02AM from the taking-away-all-the-mystery dept.

schliz writes "Scientists have identified nanoscale changes in aging lithium-ion batteries that could be responsible for their degradation over time. By dissecting and examining dead batteries, they found that some lithium was irreversibly lost from the positive to negative electrode of dead batteries, and no longer participated in charging and discharging. They discovered that finely-structured nanomaterials on dead batteries' electrodes had coarsened in size, and theorise that the coarsening of the cathode may be responsible for the loss of lithium."

19 of 108 comments (clear)

Planned obsolescence by EmagGeek · 2010-10-20 00:13 · Score: 2, Funny

I thought that's the way they were engineered - to generate revenue by way of having to replace them annually.
1. Re:Planned obsolescence by sakdoctor · 2010-10-20 00:19 · Score: 2, Interesting
  
  We've come a long way since replacement batteries that cost as much as the laptop/phone did in the first place.
  Order some generic cells and get soldering.
2. Re:Planned obsolescence by Lord+Byron+II · 2010-10-20 00:23 · Score: 2, Insightful
  
  Apparently, you've never owned an Apple product.
3. Re:Planned obsolescence by Anonymous Coward · 2010-10-20 01:05 · Score: 3, Funny
  
  We don't count Apple products in the realms of Progress.
4. Re:Planned obsolescence by beelsebob · 2010-10-20 01:18 · Score: 3, Informative
  
  Modern lithium polymer batteries survive best if you keep cycling them regularly, but *not* deep cycling them. Regularly discharging to 30-70%, and then charging again keeps them nice and healthy. Running them down to 0% all the time drives charge backwards through some cells, and helps cause early death.
5. Re:Planned obsolescence by cgenman · 2010-10-20 02:09 · Score: 2, Informative
  
  I just found a power setting on my new Ideapad that keeps the maximum charge at %80. You lose 1/5th of the runtime in the short term, but you should be able to get a much longer total runtime over time out of it, especially if you keep it plugged in. Thank you, Lenovo.
  Which brings to my next point: DON"T KEEP YOUR LAPTOP PLUGGED IN. Charge it, then unplug. The battery will last much longer if you continually cycle it, rather than if you try to keep it topped off all of the time. I've toasted batteries in 6 months by keeping them plugged in for too long. Use them like batteries, or they will die.
  
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  The ______ Agenda
6. Re:Planned obsolescence by sakdoctor · 2010-10-20 03:09 · Score: 2, Insightful
  
  Do I need to remind you that you have a choice in what products you buy?
  Buy something that is open/hackable/geek friendly.
  Buy batteries that can be rebuilt by the user using only a screw driver and soldering iron.
  Buy laser printers that have a toner refill port.
  Buy routers that can be reflashed with your choice of firmware.
  Who gives a FUCK about apple. Why does /. even have an apple section?
7. Re:Planned obsolescence by commodore64_love · 2010-10-20 06:13 · Score: 2, Informative
  
  >>>Regularly discharging to 30-70%, and then charging again keeps them nice and healthy.
  I like to use a dog analogy. If you feed your dog until he's overweight, then don't feed him until he's skeletal, and then feed him again til he's overweight, then don't feed until he's skeletal... your dog won't live long. The stress will shorten his life. ----- The same is true for batteries. Overcharging and then draining them to empty stresses the cell. The ideal is to hold the battery between 60% and 90%, avoid stressing it, and thereby extend its life. That's what Toyota and Honda do to extend their hybrid battery life longer than the gasoline engine.
  On another note:
  I like NiMH (nickle-metal hydride) better than Lithium. They only hold 75% as much energy but have a very long lifetime (over ten years if not abused), and when they do start showing age, and dying after just a few hours, a "refresh" cycle in a charger will restore them to like new condition again. Plus they can be tossed into landfills because they are environmentally neutral (no mercury, no cadmium, nothing hazardous).
  
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  "I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
Keyword slapping strategy. by 140Mandak262Jamuna · 2010-10-20 00:14 · Score: 2, Insightful

Every decade they find some keyword and the slap it on everything in sight. In the past they have indiscriminately slapped "motor" "radio" "jet" "aero" "bio" "e-" ... Now it is "nano".
Gimme a break. These batteries are based on electro-chemistry. You know, interactions between molecules. Everything that goes on in batteries, all batteries, are nanoscale, by definition. Corrosion in the electrodes had been known and studied for ages. It is a damn chemical reaction that will happen at molecular level.

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sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
1. Re:Keyword slapping strategy. by Lord+Byron+II · 2010-10-20 00:25 · Score: 3, Insightful
  
  Sure, the net effect is at the macro-scale. But we now have the ability to look at these systems at the nano-scale and investigate why the "damn chemical reaction" gets going in the first place. "Nano" here says more about the equipment used to look at the battery than the battery itself.
2. Re:Keyword slapping strategy. by jeffb+(2.718) · 2010-10-20 00:37 · Score: 4, Informative
  
  Really? You're complaining about using the term "nano" to refer to structures bigger than molecules but smaller than the wavelength of light?
  By the same token, everything that goes on in your body is based on bio-chemistry, and therefore "nanoscale by definition". But it's still useful to distinguish (for example) biochemical changes in bone digestion due to biphosphonates from microscopic changes in bone structure associated with osteoporosis from large-scale changes associated with being run over by a truck.
  The nanoscale structure of battery electrodes, larger than individual molecules but smaller than the wavelength of visible light, is absolutely critical to optimizing battery performance. It's distinct from the battery's basic chemistry, it's distinct from gross electrode shape and size, and it's certainly distinct from the macroscopic and chemical changes "studied for ages" in association with corrosion.
3. Re:Keyword slapping strategy. by Rogerborg · 2010-10-20 01:22 · Score: 2, Funny
  
  Yeah, I wish I'd had one of those fancy-pants "nanoscopes" to look at slides of fly wings and flower pollen when I was a lad - we had to make do with primitive "microscopes".
  
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  If you were blocking sigs, you wouldn't have to read this.
4. Re:Keyword slapping strategy. by shadowofwind · 2010-10-20 01:29 · Score: 2, Insightful
  
  Some others...hi-fi, cyber, eco....
  Other words are also used for their positive or negative connotation, stripped of other meaning. An example that comes to mind is when people say that something rocks. A song, a radio station, a musician, or a band can rock. Nothing else can rock, sorry.
  I've noticed that many people with "good" language skills wield words easily because that's how they think. When they hear a new phrase they get some sense of its meaning, and subsequently use it where it seems to be appropriate. But it seems they don't actually have thoughts aside from their collection of phrases. If an idea doesn't map neatly to the syntax of whatever their primary language is, its not even real to them. On the other hand, some people who are slower with words struggle with language because they're not thinking in cliches, and have the challenge of figuring out how to contort their thoughts into words. These people appear stupid to those in the glib class, but in a substantial way they're actually smarter. (Of course, lots of really smart people are good with words, and lots of people who have trouble with words are stupid in other regards also.)
5. Re:Keyword slapping strategy. by russotto · 2010-10-20 02:24 · Score: 2, Insightful
  
  Gimme a break. These batteries are based on electro-chemistry. You know, interactions between molecules. Everything that goes on in batteries, all batteries, are nanoscale, by definition. Corrosion in the electrodes had been known and studied for ages. It is a damn chemical reaction that will happen at molecular level.
  They're not talking about the chemistry, though. They're talking about structural changes. So while the "nano" may be annoying, it's appropriate. Still, this doesn't sound any different than already well-known mechanisms in lithium and nickel batteries. But being a good Slashdotter I only looked the summary, and that I only skimmed.
Re:News? Not news. by nedlohs · 2010-10-20 00:38 · Score: 3, Insightful

And instead of just taking the "attributed" reason they bothered to do some work and report on what they suspect is the actual physical/chemical cause rather than just a catch-all "disorder". Since that helps with trying to reduce the problem.
Why didn't you do that sometime in the last 20 years if it was so damn obvious?
Re:WTF? by vlm · 2010-10-20 00:48 · Score: 3, Interesting

"Things degrade and break over time, especially if you use them."
How this is news ? WTF?
The article carefully avoided mentioning that the scale of the damage was not known before. In my limited chemistry knowledge I always assumed the problem was the electrodes either went into solution or gained a molecule thick film of icky-stuff that prevented the reactions.
Its bad news... If you're trying to prevent dissolving, well, thats a very well known problem and you can play games with buffer solutions and making the electrodes more or less insoluable, and all kinds of other ideas. Old tech "no problemo". Or if the problem was thin film growth, basically electroplating gone wild, thats also old tech "no problemo" with chleating agents and electropositive series and decades/centuries of metallurgical corrosion research. By old tech, no problemo, I mean its a well developed area of study, not "the great unknown", or not that the solution inevitably exists or is cheap, just that the research is likely to proceed quickly and efficiently. But what is a non-mechanical engineering solution to surface roughness getting screwed up chemically? Hmm. At this time of morning, I have no idea what the next step could be. Lots of blue sky research money getting spent, I'd guess.

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"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
Re:Solar backup by isama · 2010-10-20 01:00 · Score: 2, Funny

I woudn't google SlaveryExtreme if I were you.
Re:News? Not news. by my+$anity++0 · 2010-10-20 01:25 · Score: 2, Insightful

Oh, I'm sorry, discovering WHY and HOW things happen suddenly isn't science. The only thing that's science is doing "real work". Strangely, I used to call that engineering.
Battery Mythbusters by jones_supa · 2010-10-20 03:43 · Score: 2, Insightful

People usually have many opinions on how you should use laptop or phone batteries to maintain maximum longevity. Keep it plugged in always when possible, discharge it to 50% every now and then, or always run it from full to empty, etc.
It would be cool if we had some "battery mythbusters" who would systematically test these things with different machines and usage patterns so we could get more solid data on the subject. :)