There isn't a resource problem for batteries.

Lithium is best for mobility applications and lithium formulations are much further down the learning curve than other chemistries.

However, all of vanadium redox, iron-air, organic polymer-based, calcium salt, and sodium chemistries are very nearly competitive, or actually competitive with lithium in various grid storage niches despite being at the very beginning of their learning curves. Is there ever going to be a shortage of iron or sodium? Or calcium or carbon, for that matter? No.

No, because there are thousands of potential battery chemistries (and storage technologies other than batteries), and also because the oft-repeated falsehood that PV contains rare earths is still false.