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.
Well all those graphs show is that the cost of batteries has gone down and that as a result electric cars contain more batteries and therefore more range. It doesn’t actually show that the individual battery capacity has increased.
The third graph that indicates battery performance vs battery chemistry doesn’t really show incremental improvement it just shows general improvement but there’s plenty of battery chemistries that are worse than pre-existing ones.