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I accidentally discharge my lithium cell to 0.45V. Is is okay if I try to revive it by charging with 10mA of current till it reaches 2.5V?

cell capacity is 4000mAh.

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    \$\begingroup\$ In my experience a cell discharged to that voltage is probably damaged beyond repair. There is nothing to stop you trying, though. \$\endgroup\$ Commented Apr 11, 2022 at 11:30
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    \$\begingroup\$ Cell capacity was 4000 mAh. If you do manage to recharge it, you'll never be able to trust it again. Do not keep it, even as a doorstop. If you do try to recharge it as an experiment before recycling it, be aware of the fire risk, do it outdoors, away from anything flammable. \$\endgroup\$
    – Neil_UK
    Commented Apr 11, 2022 at 11:39
  • \$\begingroup\$ Most of them are toast, if not for the straight up capacity drop then the self discharge goes sky high. In my own cell harvest analysis, I have had several Panasonic ones which charged up from 0.00 V to full capacity and very low self-discharge. So, your mileage will vary. \$\endgroup\$
    – winny
    Commented Apr 11, 2022 at 14:11
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    \$\begingroup\$ For certain lithium ion chemistries, overdischarge will lead to the formation of physical structures that can cause catastrophic damage to the cell (e.g. lithium dendrites). Such catastrophic damage to the cell can also cause severe injury or property damage. \$\endgroup\$
    – nanofarad
    Commented Apr 11, 2022 at 14:21
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    \$\begingroup\$ Aside from the loss of capacity, LiIon cells that have been abused tend to catch on fire. Two things that make LiIon cells nice are they pack a lot of energy into a small space, and they can discharge rapidly. This, unfortunately, translates into a propensity to catch on fire and you can't put them out. If you do try to revive the cell, do it as an experiment, and then until you dispose of it properly (Google for it) keep it somewhere that it can catch on fire and not go out, and emit lots of nasty smoke in the process. \$\endgroup\$
    – TimWescott
    Commented Apr 11, 2022 at 14:55

3 Answers 3

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Throw it away. It's a huge safety risk.

Deep discharges that bring LiIon cells under about 2.5V cause irreparable damages to its internal structure.

See this document: https://www.analog.com/media/en/technical-documentation/lt-journal-article/LTMag_V18N3_Sep08.pdf. At page 9 you find this excerpt (emphasis mine):

Avoid very deep discharges below 2V or 2.5V, as this quickly and permanently damages a Li-ion battery. Internal metal plating can occur causing a short circuit making the battery unusable and unsafe. Most Li-ion batteries have electronic circuitry within the battery pack that opens the battery connection if the battery voltage is less than 2.5V, exceeds 4.3V or if the battery current when charging or discharging exceeds a predeined threshold

Another interesting reference on the subject is this: https://www.nature.com/articles/srep30248.pdf

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You can try to revive it, but it won’t actually be revived even if it pretends to. You may get a “functioning” energy storage cell out of it, but whether the cell will release this energy through the terminals, or via a bursting wall and a bunch of concentrated heat – hard to tell.

You’ll end up with a fire starter just itching to go off, with all the dangers to life and property it brings on.

Some people would just say “hey, it’s a calculated risk”. But: have they done the calculation, or are they just hoping they’ll get lucky this once…

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    \$\begingroup\$ "This once!" Exceptionalism, the self delusion that it won't happen to me, often because of misunderstanding our place in the universe: we may have been an exception, but it's almost guaranteed not to except us from negative consequences the next timw! \$\endgroup\$ Commented Apr 12, 2022 at 15:21
  • \$\begingroup\$ (Also to @OldUncleHo) Yep, this comes down to the "old" question: Do you feel lucky today? \$\endgroup\$ Commented Apr 13, 2022 at 0:25
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Short answer: NO.

Longer answer:

Provided the cell is of a descent quality - AND - you have a fireproof place to experiment (a concrete or tiled floor and walls), you can try.

If the cell wakes up, it will be no more dangerous than before.

It will probably not wake up anyway.

Be sure to turn the charging on and then off from a distance of at least 3 meters (10 feet). Safety goggles highly advisable.

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