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Degraded Electrodes Observed In Aging Batteries
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."
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.
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.
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?
"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.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
We don't count Apple products in the realms of Progress.
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.