The main drawback of using sodium instead of lithium was energy density and weight. Sodium-ion batteries achieved something like 150 Wh/kg, compared to well over 200 Wh/kg for lithium-ion batteries. That’s a competitive disadvantage that our market-driven economies simply would not tolerate at the time.
Sodium ions are three times heavier, too. Even though the sodium component accounted for only about 5% of the overall battery weight, it still made them heavier than their lithium-based cousins.
https://evgoforth.com/sodium-ion-battery-better-than-lithium-ion/