If you are referring to stationary batteries, I feel that it is...

If you are referring to stationary batteries, I feel that it is on the cusp of taking off over the next 1-2 years.

For instance, your redox flow batteries are just beginning to become implemented into preliminary projects to validate their performance. Same goes for Li-ion battery derivatives as a stationary battery alternative.

I think that the further the EV sector progresses, the commercialisation of stationary batteries will parallel it. Simply because EV batteries will validate their performance before the market start thinking about further applications and their potential growth.

Admittedly, manufacturers are beginning to slowly tackle that industry already if you look deep enough - Tesla for one has household batteries, however, they just aren't as widely commercialised. The same applies to redox flow batteries, however once again ... they are also still in their development phase and not readily commercialised yet.

I am unsure the role graphite plays in redox flow, but I assume they may constitute the properties of their cathode. Correct me if I am wrong.

This is all IMO, but it is still exciting nonetheless.