[panick21_]

Yes, for a tiny rocket and they are not using them for anything larger.

Its doable if you throw batteries out of your second stage when flying.

But no company that makes a rocket payload then maybe a few 100kg would ever use them. And for sure not launch humans or go to Mars.

Even if you assume gigantic improvements in batteries by 400% you wouldn't use if for anything major.

It has potential for in space applications as there you can charge it with sunlight.