I see no charge rate numbers so there is no way to compare. however, these sodium batteries are cheaper, do not require lithium, and are operable at lower temperatures of -20C/-4F. Sounds like a bit of a win and opens the door for battery options in cars.
And the fire safety risks are significantly reduced (thermal runaway is much harder). They can also be transported and stored completely discharged, something not done with lithium ion batteries because of it degrades them much more than regular usage.
The sodium-ion batteries are said to work satisfactorily down to -40 Celsius = -40 Fahrenheit.
-20 Celsius just happens to be a temperature for which a retention ratio was specified in the parent article, and not the limit of the operation range.
I have no idea how true this is, but the press releases claimed that both most of the capacity is retained down to -40 and that the charging speed is proportionally retain down to -40, and that this is the meaning of the operational range.
