Sodium ion batteries are chemical and can have as much capacity as you like. They just need a bit more space, but not too much more, as they are already used in

Sodium ion batteries are chemical and can have as much capacity as you like. They just need a bit more space, but not too much more, as they are already used in cheaper electric cars. "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.[82] The car has a 23.2 kWh battery pack with a CLTC range of 230 kilometres (140 mi)." And for grid storage, "slightly bigger size" really doesn't matter.