One mention I didn't see was any reference to Sodium Ion batteries. While these aren't great for EV cars (even though you can buy at least one Chinese EV with one right now), as they are physically larger and less energy dense than any Lithium chemistries. However, they have the potential to be REALLY CHEAP because they use zero of the limited supply of Lithium and instead use the very abundant Sodium...as in table salt Sodium (NaCl).
If they are developed and end up being as cheap as though possible, the positive implications for grid storage are huge! You've heard of all that extra wasted solar power in places like California, Texas, and even western China? A very small amount of that energy is already being captured and used on the grid with today's expensive Lithium batteries and its a game changer. Sodium batteries (if they deliver as hoped) could be an order of magnitude higher in value because of how cheap they could be were we don't really care they are larger and heavier.