As an imagination exercise.
Because electrons can be controlled by magnetism. Would it be possible to take advantage of a magnetic field when charging a battery? To get higher energy compression I mean. Here I don’t think super-conduction is necessary.
So my guess is that a future battery will take advantage of magnetic fields.
Further, would it be possible to use machine learning or a genetic algorithm to increase energy storage. Like an Algorithmic Battery perhaps. I wonder if you could alter many simultaneous physical parameters to increase performance. I mean in the sun as an energy storage device you have varying magnetic fields. Maybe that is not random but works like an optimation algorithm.