While its energy density lags behind lithium-ion, advantages such as faster cycling, longer lifespan & safer, non-flammable end use make sodium-ion an attractive alternative, especially for stationary uses like data center and EV charger backup storage.
https://newatlas.com/energy/natron-sodium-ion-battery-production-startt/
@johnverdon Plus, sodium is a lot easier to get your hands on...