I think scaling nuclear power would be cheaper and more environmentally friendly.
https://www.pbs.org/wgbh/nova/article/iron-air-battery-renew...
We have heard better and better batteries being just around the corner for decades at this point.
Sure, maybe a few percent better, but nothing ground breaking.
https://www.pbs.org/wgbh/nova/article/iron-air-battery-renew...