fusso
International Hazard
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Finding amount of cobalt in Li ion batteries
LIBs capacities usually have a unit of mAh (0.001Ah).
1Ah=3600C.
For every C there's 6.24150934(14)×10^18 electrons.
Hence 1Ah=2.2469433624×10^22 e-
That's 0.0373mol
If 2LiCoO2 ↔ 2Li0.5CoO2 + Li+ + e-
Then for every mol of e- there's 2 mol Co atoms
That's 0.0746mol Co
Molar mass of Co=58.933gmol-1
Hence 1Ah=4.398g of Co
If LiCoO2 ↔ CoO2 + Li+ + e-
Then for every mol of e- there's 1 mol Co atoms
Hence 2.199g of Co
Therefore mass of Co is between 2.199 and 4.398g per Ah.
Is my calculation correct?
[Edited on 12/08/18 by fusso]
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woelen
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Yes, your computation looks fine. Of course, under the assumption that all "charge" is in the form of LiCoO2. In fact, in your scheme, it is cobalt
giving charge, going from oxidation state +3 to oxidation state +4.
EDIT: On second thought, I have some doubts with this. Cobalt normally has oxidation state +2 and in some complexes it has oxidation state +3. But is
there also a form of oxidation state +4? Apparently there is in the form of CoO2. Learned something new again 
[Edited on 12-8-18 by woelen]
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AJKOER
Radically Dubious
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See, possibly relatedly, the example of associated reactions occurring in a copper metal-air-ammonia electrochemical cell at https://onlinelibrary.wiley.com/doi/pdf/10.1002/bbpc.1963067... .
Interestingly, in the Cu/O2/NH3 cell there are two electron sources. One arises from the creation of a complex with ammonia with copper moving from +2
to +1 in oxidation states. However, the recycling equilibrium reaction:
Cu(2+)L + Cu = 2 Cu(+)L' (L= a NH3 ligand)
is needed to keep generating the added electron per the reaction:
[Cu(NH3)2] (+) + 2 NH3 --> [Cu(NH3)4] (2+) + e-
In my opinion, yes there could be some added electrons also formed in the Li/Co cell, but not likely as significant unless there is also some
recycling equilibrium (perhaps even elemental cobalt presence as wishful thinking...).
As a side note, in the case of the Cu/O2/NH3 reaction system, those added electrons are, per my suspicion, the reason for the creation of nitrite (as
in the NH4NO2 side product) in the active presence of oxygen, so perhaps not without potential chemical consequences.
[Edited on 6-9-2018 by AJKOER]
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