No, you are factually incorrect here. Molten salt batteries, as the name implies, are still batteries aka galvanic cells.

Or as wiki itself puts it: > Molten-salt batteries are a class of battery that uses molten salts as an electrolyte and offers both a high energy density and a high power density.

The Ambri cells ARE molten salt batteries, that doesn’t imply anything about the state of matter for the electrodes. The cells have a molten salt electrolyte (obviously, there aren’t many alternatives at these temperatures) and have at least one molten metal electrode. It doesn’t matter if it’s direct electrodeposition or alloying. Likewise Aluminium ion batteries would still be that, no matter if they use tin metal to form an alloy or if they use direct electrodeposition from say an ionic liquid.

And to back it up additionally, see Wiki again:

> Ambri, Inc. is an American startup company which aims to produce molten-salt batteries for energy storage in wind and solar power systems.[1] In 2016 it had thirty-seven employees.[2]

But thermal energy storage by utilizing the infinitely high heat capacity during solid-liquid transitions of salts is definitely a thing as well.