There are also interesting things happening on the non-mobile battery front, notably vanadium flow. Energy storage is in a liquid, so battery charge/discharge capacity is decoupled from the amount of storage a battery can hold (need more storage, add fluid capacity).

This is currently appropriate tech for grid-scale providers, but, as it progresses, it will be so for smaller sites (individual buildings and microgrids). IMO important as heat pumps replace combustion in places where grid electricity might be interrupted for days. Also, as a resource, vanadium is more available than lithium.