Sodium-ion batteries will always be heavier than the best lithium-ion batteries, but for now they have the same energy per kilogram with LFP batteries.

So they have 2 essential advantages over LFP, retention of capacity to much lower temperatures and their cost will become significantly lower when their production technology will be more mature, because they not only do not use lithium, but they also do not use other expensive substances, e.g. nickel or cobalt.