Lithium fluoride sounds like battery chemistry that makes things even more fun when things go wrong...

Thank you for this info. Now I realize why I heard some chatter about lithium bromide batteries a while back. Probably the "easier" to work with and cheaper instead of gold/chlorine/fluorine.

Sodium-bromide in particular looks like a cheap, highly available, easy to handle pair that can fill every one of those niches that don't really care about energy density.

But current batteries use metal compounds, where the metal itself is never completely oxidized or reduced. Those are much easier to design, as you can simply place an ion exchange membrane separating the poles. AFAIK, nobody has any idea how a metal-halogen battery would work.