These batteries ditch the iron for something much cheaper: lithium

https://www.fastcompany.com/90716101/these-batteries-ditch-the-lithium-for-something-much-cheaper-iron

"Unlike lithium, iron abundant element... Tesla incorporate iron into their lithium batteries to replace other rare minerals, like cobalt. An iron-air battery discharges power slowly, so it isn’t a good fit for an electric car, but it works well for dispensing energy over days to the electric grid. For the grid, it will make sense both to have technology that can quickly respond to provide boosts of power, like lithium-ion batteries, and something like iron-air batteries to store power over longer periods"

Related:

Tesla's Next-Gen Electric Motors Will Get Rid Of Rare Earth Elements

https://insideevs.com/news/655233/tesla-next-gen-eletric-motors-no-rare-earth-elements/

AI breakthrough could replace rare earth magnets in electric vehicles

https://www.sciencedaily.com/releases/2026/02/260218031611.htm