A surprising breakthrough could help sodium-ion batteries rival lithium—and even turn seawater into drinking water. Scientists discovered that keeping water inside a key battery material, instead of removing it as traditionally done, dramatically boosts performance. The “wet” version stores nearly twice as much charge, charges faster, and remains stable for hundreds of cycles, placing it among the top-performing sodium battery materials ever reported.
They have slightly lower density right now, but there is work to increase the density, and it could very well get up to about 210wh/kg which would put it directly on par with current lithium ion batteries. So it could replace the low end of the EV market without any significant change except for a reduction in price by a lot.