“The lower energy of the sodium-ion cells suggests that the technology may be more suited for stationary energy storage applications which are less restrictive, while the unveiling of battery packs combining both sodium-ion and lithium-ion cells could point towards compromise in performance for low-cost electric vehicles, with the potential to disrupt the mass market,” 

CATL now has a battery combining both technologies that may just serve as something to ignite the "low-cost electric vehicle market".

It isn't something for everybody.  Compromise rarely pleases everyone, but it is something that we may be seeing in the future to expand the totality of EVs within the overall automotive market world wide.

It is important to note that this pairing of the two different technologies into one battery still incorporates lithium as part of the solution.  This in a day when lithium investors have concern about possible replacements for lithium in the future of batteries.

Keep in mind that CATL is not exactly a "Mom and Pop" battery company.  They are fully entrenched as a card carrying member of the Lithium Battery Manufacturers "Big Boy Club".  A charter member, if you will.

See the article from Mining.com:

CATL, Tesla battery supplier, unveils sodium-ion battery - MINING.COM