There are sodium ion batteries available at aliexpress. The claimed advantges (written in an unintentially comical way) are:

- better safety

- same number of cycles as LiFePo

- much better capacity at low temperatures

- protects environment (?)

I would take that with a truckload of salt. Also, price is roughly 50% higher than LiFePo.

On many product images there is an outdoor winter scenery. So performance at very low temperatures seems to be the main selling point.