Technology

If you use lithium batteries, sure, but grid-scale solutions are definitely moving away from that, the only reason Lithium ever really showed up in the grid is because car manufacturers built up lithium capacity, it wouldn't have happened without that. Lithium itself I think won't be an issue for long, plenty of abundant repositories have been found and we haven't even really started recycling, cobalt now that's a completely different topic.

Main difference is that you really don't need energy density if you don't lob the batteries around all the time so flow batteries, sodium-ion, molten salt, whatnot, are very enticing options. For spikes and frequency regulation there's good ole flywheels (which came for free with all those glorified steam engines burning fossil fuels and uranium). Also around here we're using Scandinavian hydrodams as storage for our wind, granted not everyone has them as neighbours.

A bit further down the line power-to-X will also be an important factor in backup and seasonal storage: We'll need various hydrogen/hydrocarbon compounds anyway as feed stock, for steel smelting etc. so production capacity to soak up renewable overproduction will be available. Which side note is also the reason people should stop with the "hydrogen is dirty" argument: What the fuck else are you going to smelt steel with. Right now hydrogen smelters are going to use fossil hydrogen, yes, but that's pretty much the only way to build up enough demand so that green hydrogen production gets investment.