But doesn't EVERY new chemistry provide 10X density and will be ready in 3 to 5 years??
As for me, I don't think I'll be holding my breath.
As to lanthanum:
Lanthanum oxide was priced at 7,810 U.S. dollars per metric ton in 2017.
Although classified as a "rare earth element", it's actually more abundant than lead, but costly to produce.