"The advantage with Sodium Ion is that, although energy densities are lower than Lithium Ion, it could still be used to power mobile devices and electric vehicles."
It already does.
"Chinese automaker Yiwei debuted the first sodium-ion battery-powered car in 2023. It uses JAC Group’s UE module technology, which is similar to CATL's cell-to-pack design.[84] The car has a 23.2 kWh battery pack with a CLTC range of 230 kilometres (140 mi)"