Tmt, Lockheed martin australia, page-2

Likely not vanadium IMO. Though they are being deliberately coy.
https://www.lockheedmartin.com/en-us/capabilities/energy/energy-storage.html
Just another competitor in a ridiculously crowded market.
The US is announcing massive new grid storage batteries atm. Using lithium-ion.
Seems VRFB is just not happening unfortunately.
As to why....who knows? PR of Elon/higher upfront costs/decision maker knowledge gaps/simply not as good as we hoped?....A mix of it all I guess.