I have access to a large number of dead LiSOCl2 AA cells - over 50 of them, and I'm trying to decide whether its worth extracting the
lithium chloride from them.
A dead cell should contain LiCl, S, SO2 and some residual SOCl2. There is also a lot of carbon forming the cathode current collector, in powder form
I believe. There will be little, if any, lithium metal. Not sure of the case material - I can't find any data on that. Probably stainless steel.
The process envisaged would be to dump the cell contents into distilled water to dissolve the LiCl and hydrolyze any remaining SOCl2. Filtering would
remove any solids (carbon and sulfur), leaving a solution of LiCl, HCl and SO2.
Boiling this down would drive off the HCl and SO2, leaving the LiCl.
I guess its possible I might end up with some lithium sulfite as well, not sure.
Comments appreciated.Sulaiman - 18-2-2024 at 22:07
I have a box of old 123 size cells, one of which I opened to extract the lithium foil.
The quantity of lithium in an unused cell is proportional to the Amp.hour capacity,
so there should be a good ammount of lithium in an AA cell.
"worth"...... for the education, yes
economically, no
(assuming that you can buy lithium, or in this case lithium chloride)
PS I just realised that I don't remember disposing of the batteries before the removal people packed up my lab/shed stuff
- so I may have a box of them here - somewhere.
They are very old by now, probably in a similar condition to fully discharged,
So
It is now imperative that you develop and publish a complete extraction, recovery and refining protocol
[Edited on 19-2-2024 by Sulaiman]Twospoons - 19-2-2024 at 13:50
It is now imperative that you develop and publish a complete extraction, recovery and refining protocol
[Edited on 19-2-2024 by Sulaiman]
Ha! Yes, I promise you a nice write up if I proceed.
Li compounds seem surprisingly expensive from my local chem supplier - $130 (NZ) for 100g of LiCl ? It is lab grade though.
And since the batteries wont cost me anything but a Saturday afternoon...
*sigh* I guess I just added another project to the list. Twospoons - 25-2-2024 at 14:44
Tried taking apart one cell. The body is a deep drawn steel can, so i used a pipe cutter to cleanly remove the ends. There was an audible hiss of
escaping SO2, and a distressing smell (I was outside and upwind, but still caught a whiff). After scraping the contents out of the can I dumped the
lot into about 100ml of distilled water. Some fizzing from the can indicated a trace of metallic lithium remained. The cathode material was thick,
black, and did not wet. There were also some obvious bits of sulfur.
I added about 5ml of HCl to convert any LiOH to LiCl, then filtered through paper to removed the solids. The filtrate was cloudy, so I filtered again
through a 40um glass frit. Still left with a trace of cloudiness which settled over time time - most likely fine sulfur particles.
Its drying in a dish now.
Next time I might try liquifying the cathode first by soaking in toluene or xylene (paint thinner or brush cleaner), as the scraping part is a PITA.
With any luck that will dissolve all the sulfur, and make subsequent processing easier and less stinky.
This whole thing is probably more trouble than its worth, but its still keeping me entertained.j_sum1 - 25-2-2024 at 16:15
This whole thing is probably more trouble than its worth, but its still keeping me entertained.
I found dismantling the batteries really difficult even with a pipe cutter. And sorting the various bits inside and processing them required buckets
and large amounts of mess.
I stopped because I was no longer being entertained.Sulaiman - 25-2-2024 at 23:44
Assuming that I find my box of batteries
that I guess are partially or fully self-discharged:
From memory... the outer steel casing had a folded seam that could be torn apart,
but I'm considering first recovering any remaining thionyl chloride (bp <80oC) by 'dry distilling' a batch of opened cells.
Maybe I'd get a useful product,
at least it's eliminated before further processing.
Does this sound like a viable first step?
Or
Does it sound like a very exothermic hazard?
I'm thinking ahead, not ready yet and maybe I have no batteries. Twospoons - 26-2-2024 at 14:05
If they had a folded seam they may not be thionyl chloride batteries - it would be hard to make a seal good enough to contain the pressure from the
SO2 that is produced during discharge. Check the specified cell voltage written on the side: 3.6V => LiSOCl2, 3V => MnO2Sulaiman - 12-3-2024 at 13:11
I just came across my box of batteries!
Not as many as I thought - 14 pieces.
I took the wrapper off of one to find a shiny seamless case with a deeply crimped neck.
I measured three... 3.267, 3.265, 3.267 volts! (+/-0.5% dmm)
I hope that means there is still mostly un-oxidised lithium foil to recover... when needed.
[Edited on 12-3-2024 by Sulaiman]Twospoons - 12-3-2024 at 14:23
That voltage would suggest you have Li Mn cells. Sulaiman - 13-3-2024 at 02:14
I just checked the datasheet for the cells; Li/MnO2
Well spotted - thanks
Here is a guide on how to do it.
Monoamine - 29-3-2024 at 23:49
Hi Twospoons,
Yes, I have done this successfully before. I wrote a detailed report on how to do it and what to expect here in this thread.
Basically, you will get a very contaminated brown thionyl chloride liquid out. You can then redistill this to get pretty pure SOCl2 (you'll
need to scroll down a bit).
