[imtringued]

Lithium does not suffer from undesired pigmentation and overabundance of too many completely different types of lithium the way plastics do. Plastics are composites so if you were to extract the elements out of them then you would end up with carbon and hydrogen which unfortunately aren't plastic. With lithium all you have to do is extract the lithium elements.

Aluminum and iron recycling is viable because they are elements in their own right.