Re: Li-ion battery costs.

https://techxplore.com/news/2021-03-reveals-plunge-lithium-ion-battery.html I've been following magnesium-ion batteries for a few years.

https://en.wikipedia.org/wiki/List_of_battery_types https://en.wikipedia.org/wiki/Comparison_of_commercial_battery_types Some people are using nickel-iron NiFe for home... cheap, easy to maintain, simple chemicals, last forever, simple charging, take lots of abuse. Others pull ions from junked car packs. Or just plain lead-acid.