Thank you for pointing out the missing link: https://news.mit.edu/2023/mit-engineers-create-supercapacito...

> Also, cement is not very sustainable because of CO2 emissions.

Agreed that cement is a CO2 issue, but I think the overall environmental savings of not having to refine and transport lithium far outweighs the cost of the cement

Also the cement batteries are *very* simple to construct; it only takes a 4th grade education and can be made from locally sourced materials