Li-ion battery recycling at home

[jonescg]

Yeah so right now I'm working exclusively with Lithium cobalt cells, cause that's what I have lots of. LiCoO₂ and H₂SO₄ -> Li₂SO₄, CoSO₄, and a bit of O₂. The extraction is quite efficient for Cobalt, but it does take aluminium with it. Hence the precipitation with NaOH and to excess, ensuring the Al goes back into solution as aluminate anions. This is rinsed out and the hydroxide is resuspended in dilute H₂SO₄. Then its a case of boiling down and recrystallisation of the CoSO₄·7H₂O.

The next step is to scale it up and devising a system for taking shredded cells and separating the polyethylene. The copper and cathode materials will settle in a float/sink tank, but it needs to recycle the water otherwise the volumes get out of control. Acid digestion will leave the copper alone. If anything it will be easier to separate afterwards.
Lots to experiment with

[ Edited formulae: guess who? ]

[Bukes]

Also, do you have any pictures of the cathodes / electrodes pre-milling? I'd be interested in testing some of them in my hydrogen production setup. May be able to recycle them without destroying them and going through all of the chemical challenges.

I'm also looking at Urea fuel cells, which use a nickel-cobalt catalyst. I wonder if we can produce something with your CoSO₄ salt?

[jonescg]

You are most welcome to my cobalt supplies!
As for the electrodes, they're nothing special - just a foil of copper or aluminium with black stuff coated on them. It would be a lot of work to pull them apart, but if you could put them in solution and pass current until the black stuff just falls off, it might be valuable. I doubt that aluminium will be much use to you as it's such an active metal, but the copper might be of some use.

PS thanks Coulomb!

[T1 Terry]

Also, do you have any pictures of the cathodes / electrodes pre-milling? I'd be interested in testing some of them in my hydrogen production setup. May be able to recycle them without destroying them and going through all of the chemical challenges.

I'm also looking at Urea fuel cells, which use a nickel-cobalt catalyst. I wonder if we can produce something with your CoSO₄ salt?

You sure not just taking the p*ss here

T1 Terry

[jonescg]

This is what the electrodes look like.

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[Bukes]

Also, do you have any pictures of the cathodes / electrodes pre-milling? I'd be interested in testing some of them in my hydrogen production setup. May be able to recycle them without destroying them and going through all of the chemical challenges.

I'm also looking at Urea fuel cells, which use a nickel-cobalt catalyst. I wonder if we can produce something with your CoSO₄ salt?

You sure not just taking the p*ss here

T1 Terry

[Bukes]

Hmm

Here is an article on making bi-metal nickel catalysts for direct urea fuel cells. It goes into detail for the nickel palladium bi-metal, but I’m sure a similar method would work for nickel cobalt (which it also discusses). Here they’ve added phosphorus to the mix, which is worth considering. And they’ve used nickel-chloride and palladium-chloride as the salts.

https://www.frontiersin.org/articles/10 ... 00777/full

They embedded the catalyst on a carbon nanotube structure. graphite felt may work pretty well and it’s readily available and cheap online.

Then we would need a cation exchange membrane. I’ve been meaning to try making one out of sulfonated polystyrene (in theory should be able to grate up polystyrene and mix it in sulfuric acid at 80 degrees for 3 or 4 hours, then press the goop into a thin membrane).

—edit — gah, we need an anion exchange membrane, not a cation exchange membrane. They can be purchased but are still $$. Need to research to see if there’s a way to make one without a chemists lab…

[Bukes]

This is a good video on creating membranes… only uploaded to YouTube 5 days ago! I’ve been looking out for one for a while
https://youtu.be/tiMt4tIced8

[Bukes]

Hmmm, interesting paper on lithium purification (from seawater brine) using ion exchange membranes and electrodialysis. Lithium ions are cations. Also, the original membrane / separator in the batteries may be a lithium ion exchange membrane already…

https://www.nature.com/articles/s41467-019-13648-7

[jonescg]

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This is the resulting hydroxide precipitate when you don't use peroxide. It's much cleaner and a bit less sludgy. I still decanted it and washed with 25 litres of rainwater (as close as I can get to DI water). Resuspended it in dilute sulphuric acid and filtered the residual black crud, and boiled the solution down until it looked like merlot, or at least a dark shiraz. Should have CoSO₄·7H₂O crystals in the morn.

Time to find a couple of 200 litre drums for large scale reactions.

[jonescg]

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CoSO₄·7H₂O crystals from a seed crystal in the middle of the flask. There's about 50 g here.

[Bukes]

Very pretty!

[jonescg]

Just another picture of some pretty recycled cobalt sulphate crystals:

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[coulomb]

some pretty recycled cobalt sulphate crystals:

Needs a garnish Otherwise, looks delicious.

[jonescg]

Speaking of making a mess in the kitchen. As always in life, never charge a battery unsupervised, and never boil a concentrated cobalt salt solution unattended...

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[Bukes]

[jonescg]

Today the Future Battery Industries Cooperative Research Centre opened the Cathode Precursor Production Pilot Program - the FBICRCCPPPP (yes, for reals).
Here they do batch and continuous metal sulphate solution mixtures and precipitations which are then filtered, dried and sent to Brisbane (QUT Gardens Point) for lithiation and calcining. There they will test the different formulations for energy density, cycle life, etc etc.

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Very cool place to visit, and they are very open about visits and tours. AEVA WA might make a trip here later in the year.

[jonescg]

I finally got a chance to try CD Dodd's 22 kW rotary shredder - you know, the kind there's a billion Youtube videos of.
It made light work of shredding up the old Voltron battery packs I'd stored for a year, as well as an old CALB cell for interest.
The resulting shredded material was fairly uniform, but if you were to do any winnowing or gravity / wind based separation it would need to be a bit finer. I have had some success with a float-sink technique, but if you get an axial shred it forms a ribbon, or streamer which gets tangled in the metals and weighed down. Hence the need to do a finer mill of the output.

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You could feasibly go straight to the acid digestion stage, but the plastic really just gets in the way. I'm currently researching some simple winnowing or shaker table style separation systems.

[jonescg]

I have started an experiment to determine how best to deal with aluminium in the mixture. Aluminium is present as the main conductor for the cathode, but only represents about 8% of the mass of a Li-ion cell. The cathode is really well attached to the aluminium, and it only really liberates the cathode active material with dissolution in sulphuric acid. But then you need to deal with a mixture of solid copper and aluminium, as well as the dissolved metal ions of nickel, manganese and cobalt.

So I have decided to try completely dissolving the aluminium with an excess of H₂SO₄, filtering the residual carbon/copper mixture and precipitating the aluminium with NaOH. Then keep going with the NaOH until the AlOH₃ re-dissolves into sodium aluminate, NaAlO₂(aq). The experiment starts with 17g of copper foil and 8 g of aluminium foil.

About 2.8 M H₂SO₄ was added and stirred for 48 hours. The aluminium eventually all dissolved, and the copper was left right alone.

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I will neutralize the remaining acid, precipitate the Al(OH)₃ and keep going with the NaOH until the precipitate re-dissolves. At this point, you can wash it, and the sodium sulphate out form the metal hydroxides, and dispose of them in the sea (or somewhere safe).

[jonescg]

So I have filtered the copper and washed with water several times - prettymuch 100% recovery. As expected, as it won't dissolve with H₂SO₄ unless H₂O₂ is present.

Next step was to begin to precipitate the aluminium from the clear solution of Al³⁺ ions in dilute H₂SO₄ using 10 M NaOH. Every 100 ml was 1 mole of NaOH.
Stoichiometrically speaking, 1 mole of H₂SO₄ was already used up to react with the aluminium, and there was an additional 1 mole of H₂SO₄ as an excess. So 2 moles of NaOH are needed to neutralise the excess mole of sulfuric acid, and an additional 1 mole of NaOH is needed to turn all Al₂(SO4)₃ into Al(OH)₃.

pH still below 6 here:

Al Cu H2SO4 experiment 3.jpg (181.85 KiB) Viewed 406 times

Then, after adding 3 moles of NaOH (300 ml of 10 M solution) all the Al(OH)₃ precipitated as a giant gluggy mess!

Al Cu H2SO4 experiment 4.jpg (150.49 KiB) Viewed 406 times

So my real question was to see if I could take the pH well past neutral and get all of the aluminium to go back into solution. Again, stoichiometrically speaking, an additional 1 mole of NaOH is required to react with the newly formed Al(OH₃) gloop, to form NaAlO₂. So after adding a total of 5 moles of NaOH:

Al Cu H2SO4 experiment 5.jpg (177.31 KiB) Viewed 406 times

Effectively a clear solution, with what might be super-fine aluminium oxide as a solid residue. I'll have to filter it and find out.

[4Springs]

Glad to see you've progressed from jam jars to Schott bottles!
Still no gloves though...

[jonescg]

Bloody things arent cheap either. But yeah stay away from the mouth of the bottle, and don't lick your fingers are good rules to follow.

Sodium sulphate makes pretty crystals at least.

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And thanks to @coulomb for subscripting for me!

Now, time to write an SOP for 100 kg of the stuff.

[T1 Terry]

Can the aluminium be extracted using electroplating or electrolytic refining?

T1 Terry

[jonescg]

Potentially yes. It would be difficult to ensure the newly formed aluminium doesn't immediately oxidise, but it would be a lot easier to take it out of solution than molten cryolite.