When a smaller nation aligns itself with a larger empire or coalition, it will gravitate towards that collective's philosophy. Sometime's it's imposed through political or military pressure, or "encouraged" through subversion, but it can just as easily happen through the natural influence of a larger and more prolific culture.
Sodium batteries are commercially available as of early this year. I've seen Hakadi and Sriko tested independently on Youtube -- they're the real deal (sodium has a unique charging curve), but they have the same/similar organic electrolyte as LFP cells (I believe Natron uses PBA on both anode and cathode plus water-based electrolyte).