Here is a fairly digestible breakdown of sodium ion battery chemistry.
It's a promising technology, but clearly lithium ion won't be disrupted by it in the short or medium term.
Take Chinese EV range claims with a grain of salt. Some are wildly optimistic vs EPA test cycle. And ludicrous ranges are just sensationalist. Anything beyond a real world range of 400-500km is just needlessly driving up the cost and weight of the vehicle. One could make a car with a 2000km range, but it would be very expensive, heavy, handle poorly and have poor cabin space and payload capacity.
There are four common EV range tests that have been in use all over the world. These are EPA, WLTP, NEDC, and CLTC.
www.licarco.com