> cobalt, a very toxic heavy metal
Cobalt is neither particularly toxic nor a heavy metal. In fact, it's a part of vitamin B12. You might be thinking of Cadmium, which is indeed a very toxic and nasty metal.
In LiPos the heaviest metals are Iron and Nickel. That's by design. Heavier metals tend to be more expensive to procure.
In trace amounts, by both weight and volume lithium batteries are mostly nickel and/or iron.
> There are other toxic substance like phosphorus in "lithium" batteries. Some "lithium" battery chemistries
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> BTW, lithium itself is highly toxic too.
Both phosphorous and lithium are fertilizers. Yes, taking in a very large dose of both is poisonous, but the same is true of salt.