The reason lithium is used for batteries is that it is an excellent anode the lightest metal. Lithium will always be used for batteries that need to be light.
Sodium is not fundamentally better material than lithium, though. It's just a bit more abundant (but lithium is very abundant and can be extracted from actual ocean water, though because of lithium's abundance, that will never be the cheapest way to get lithium).
Lithium is the third lightest element and the lightest (regular) metal. Sodium is much heavier.
Battery based on aluminium theoretically can have much better capacity than lithium both per volume and per weight. But it is much harder to make batteries from it. Still there were a progress of making non-rechargeable fuel cells based on aluminium. As aluminium is safer to handle even compared with gasoline, loading/unloading few bars of it from a car should not be a problem.
We can't be sure that there won't be a breakthrough that will make all our phones and cars run on adenosine triphosphate, like everything else on this planet. But right now we have to work with what we have, and whatever knowledge and experience we thus gain will likely be useful post-unexpected-breakthroughs anyway.
In terms of energy density, maybe, but the magic of ATP is the whole process of creating it and the precision with which it is used to power things :).
Yes we can, because "breakthroughs" don't happen over night. There's often at least a decade between the first lab result and wide industrialization of technologies like these. That means you can use today's lab results to predict the "breakthroughs" in 10 years.
I'm no expert whatsoever but if there's no promising lab results currently for lighter batteries than lithium, then I doubt they'll be replaced any time soon.
