There’s this new company called Duracell that’s making these AA batteries which seem promising too

I heard about these sodium-ion batteries a few years ago. I don't really care much about these until they are actually in the market.

Happens when there is a lot of public interest in some sector...

But in this case it actually isn't "new technology". The idea is as old as lithium-ion batteries and equally solid. But back then (the 1990s) people saw greater potential in the more expensive (material-wise) lithium-ion batteries because for mobile electronics starting to become big energy density was more important than prize/ressources, so that's were the money to develop and improve mass production went.

Now that there is interest for a product on a scale were required ressources are the more important factor than seize and weight (grid level energy storage for example) it's only natural that those existing concepts are revisited everywhere as those concepts are usually already developed to "ripe for production" levels and all that is missing is the investments to build production up large scale... cost and efficiency improvements then happening naturally included. I mean... just look up how lithium-ion battery performance improved in the last decades without any actual technical improvements, just by optimizing processes with the experience from scaled up production.

Battery capacity has almost tripled in the last decade.