[Robotbeat]

Don’t need manganese or any rare minerals for batteries. Lithium iron phosphate batteries are used in the least expensive Teslas (base Model 3 and Y), and although lithium is very abundant, you can even substitute it for the even more abundant Sodium with only a slight weight increase. That’s superior to Lead based batteries in nearly every way.

[pfdietz]

Manganese is not a rare mineral. One does not mine manganese nodules for the manganese. Mining them would create an enormous surplus of manganese that would get dumped in waste piles.

[Turing_Machine]

Why is a "waste pile" worse than having it distributed all over the ocean floor?

[pfdietz]

I wasn't making a judgment here. I was just pointing out that most of the manganese ends up in the waste stream. One would not be mining these things for the manganese (although what manganese that could be sold would be sold.) In a world mining manganese nodules, the price of manganese would be very low.