The sodium-ion battery (NIB or SIB) is a type of rechargeable battery that uses sodium ions (Na+) as its charge carriers. Its working principle and cell construction are almost identical with those of lithium-ion battery (LIB) types, but replace lithium with sodium.
It looks like Nio is going to use solid-state batteries from 2024 onward. That seems pretty tangible to me. BMW and Ford are said to be working on integrating batteries of this type, too. No miracles necessary.