Years ago, a lab next to the one I worked in had experimental
batteries under development. All the high energy density ones utilize
very reactive elements, of which lithium is one. However, nothing
would beat the sodium-sulfur battery in its capacity to "go
Vesuvius". It was colloquially referred to as "the fire and brimstone
battery". The lab had a sulfurous smell that reminded one of the
entrance to nether regions.

I'm going to stick with lead-acid, thanks very much!

Mike