Sodium Ion batteries have started appearing

I was looking today on AliExpress and found the Sodium Ion batteries are starting to appear. 18650s and other cylinder batteries as well as pouches. They are cheap, this would give 220AH and 49.7V nominal or 10.5KWh batteries for £1400. A LiPho of similar capacity would be 2.5x that.

The have some details of the voltage curve which looks quite extreme along with what sounds like great >1C charge and discharge and 1C sustained and 6000 cycles. These are looking really good for home solar systems.