It's nickel and lithium; mainly nickel https://www.kitco.com/news/2020-09-22/Elon-Musk-sees-big-target-in-mining-costs.html
[Musk and Bragnila imagine Tesla factories processing raw nickel powder for processing.
"Raw materials from a mine go to the plant and out comes a battery," said Bragnila."
"At three terawatt-hours of battery cells per annum by 2030, that would entail approximately annual consumption of 2 million tonnes of nickel. That's almost the entire scale of the current global nickel output," said Turenne.]
The anticipated demand for nickel is enormous.