Probably over half of the utility scale storage is Lion. AES and a few other companies will sell you a storage containers full of them as a turnkey system. The levelized cost of energy for solar + storage is at 82/mwh, which is in the range combined cycle natural gas for grid regulation.
In reality, even though I don't think lion tech is quite as good as some others, they are winning on price. GM paid 600/kw for the original Volt battery and they are paying 145/kw for the Bolt.
We talk about cars a lot, but typically batteries go from cells to cars to utility. Cell phones don't have nearly as stringent rules as cars do, and Utilities tend to stay away from unproven technology and unproven companies.
Tesla is also into utility scale storage, and at one point was the largest supplier in California. California has a storage requirement for utilities so they are scrambling to install storage. like 3 gw total I think by llke 2022. There are a couple of other states with requirements, and then the California ISO has expanded their real time market based system into parts of most of the western states and they have a storage requirement as well.
As far as Lead Acid batteries go. They are going to be hard to replace. First is they work in hot and cold temps, and they can take abuse. Then you have have other cell chemistries, but they have higher voltages per cell so getting within the parameters of the nominal voltages to use with legacy equipment is a bit trickier. If you don't use legacy equipment, then you are using a new design which costs more..