Things like this keep being claimed... But the reality is that we know all of the elements available to us. And we know which of these elements in concert with one another can store energy to convert to electricity. The problem is that those elements alone are unstable, so others must be added for stability. We have already minimized those extra elements. There may be some margin to be gained, but we are close to peak energy density possible. Everyone of course hopes that there will be another breakthrough similar to what we saw between NIMH to Li tech because it would be amazing for EV's... That hope makes people believe claims like we see here. There are some experts that have acknowledged that our battery tech has mostly peaked.

https://www.bmwblog.com/2022/12/06/bmw-engineer-lithium-ion-battery-tech-may-have-peaked/