Here's Natron's page about safety: https://natron.energy/our-technology/safety

I don't think the battery is a big block of pure sodium. That would be unsafe.

The battery electrolyte contains sodium ions, but the same is true of salt water and Gatorade.

I think the industrial source of their sodium is sodium hydoxide, a common industrial feedstock. https://en.wikipedia.org/wiki/Sodium_hydroxide

One of the claimed benefits of sodium based batteries, that I remember from the press statements of CATL, is that they don't burn, even when you but them in a fire. The also should work in a wider temperature range, which is especially interesting for cold regions.

In the article it says, that they are using a "patented Prussian blue". Isn't CATL also using Prussian blue in their first generation sodium batteries?

For iPhones, at least, I believe that period was when they were thinnest (the iPhone 6 is the thinnest one, 2014).

The battery made by the company mentioned uses an aqueous electrolyte construction which is theoretically safer from what I read, but I don't know if it can be made small for a portable.

The fact it supports more cycles and tolerates a broader temperature range than Lithium counts points towards safety too. Lithium isn't happy above like 30 Celsius, which a fast charging portable device can _easily_ reach.

Since na-ion cells are available on aliexpress, youtubers already did puncture tests, and indeed they did not catch fire.

Seems like sodium is better "hidden" in the cathode/anode so it won't react witth the air so quickly as lithium when battery innards are exposed.

I believe sodium here is always in the oxidized +1 state, like the lithium in Li-ion batteries. It's not present as a metal. The things being oxidized/reduced are transition metals in one or more electrodes.

NaCl is pretty safe. ;)