Did you read the article? This isn’t about a research paper that talks about theoretical lab experiments. Sodium batteries are in real world application right now. Mainly in China and South America.

You can buy sodium batteries from AliExpress. It’s been available for a while. I was thinking about ordering a few but I ended up spending my hobby budget elsewhere. There’s no economies of scale yet for sodium battery tech. You can get the battery but there is zero electronics available for it. Mainly you’d have to design your own charger and battery management modules. That’s out of my pay grade. I’ve been waiting for Chinese engineers to mass produce such things.