Lots of choices
There are dozens of energy storage options out there, and many look great on paper. In practice? Often not so much. Lithium-ion's strong point is high energy density which is very important in a vehicle smaller than ,say, a cargo ship. But it's not necessarily a big deal for a fixed installation. In point of fact the preferred utility grade storage option is often pumped storage which is quite cheap (a few cents per kwh) if you use it a lot, have lots of water available, have suitable topography and don't mind losing about a quarter of your input energy to various inefficiencies. Pumped storage has very low energy density.
A storage vessel for molten Silicon? Let's put it in your backyard, not mine. Same for Sodium-Sulfur storage which is actually in use here and there.
Biting the hand that feeds IT
