Comment by cma

That's not the case for their new batteries:

> Moreover, independent 4680 battery teardowns and chemistry analysis shows that Tesla is still using the regular 811 nickel-manganese-cobalt mixture for the cathodes and ordinary graphite anodes.

https://www.notebookcheck.net/First-Tesla-4680-battery-teard...

They also aren't using added-silicon anodes yet, which may explain why the energy density is so poor. I'm not sure if they are having trouble working on this, or if they are waiting on patents to expire.