I hope this doesn't come off as combatative, but I don't know why people keep repeating this fun fact from their highschool chemistry class as if it's relevant to the discussion.
> The locations of suitable continental brines are also geographically restricted, with an estimated 50–85% of lithium-rich continental brine deposits located in the Lithium Triangle and with China as the next richest source. Hard-rock ores are also geographically concentrated in Australia and China
Lithium in a form that is economical to mine/process is indeed quite rare. Which is why 3 countries produce 90% of it.
And it is extremely environmentally costly which is treated as an economic externality. It takes 1.9m litres to mine one ton of lithium and solvent chemicals like hydrochloric acid contaminates groundwater, making the entire site toxic and unlivable.
Entire governments have been overthrown for access to this resource.
Actually not at the rates we're predicted to use it, no
And yes Sodium is fine for most applications where it can be a little heavier (grid uses, maybe cars) which is where most of it is projected to be needed.
Lithium is abundant, as are other "rare earths" (they are not rare), but the problem is that they are quite scattered and to extract them nowadays requires to process very large areas of land through chemical reactions (additives and evaporation).
