[cogman10]

> Can someone explain what it is that makes batteries wear out to begin with.

For lithium ion batteries, effectively what happens is little crystals start forming which cut down on total usable surface area and in the worst case short out the cell. If you've ever seen copper plating using electrolysis, effectively that is happening in the battery. The charge and discharge cycle end up pulling over materials between the cathode and anode which aren't desirable.

> them work again after they’re shredded into “black mass”?

The process of separating the component parts is something we do anyways with virgin materials. It's mostly just chemical reactions to remove desired elements and compounds and then reform them into a workable byproduct.

But what should also be stated is that by weight, batteries are mostly metal. It's a metal foil coated in a thin layer lithium goo. Even if we simply ignored the lithium goo, most of the metal could be recycled by simple melting down the metal foil and jacket.

The goo has valuable elements which is why there's effort to recycle it.