Toyota and a few other companies have been researching this as well.

The output was an issue and charging them was an issue/expensive to manufacture. When charging the solid state battery would cause a type of leak (oversimplifying this) and to manufacture it correctly would cost a lot.

We’re seeing the early adopter phase of the EV I feel like. Obviously the whole process isn’t green, it will take time for that. Same goes for the batteries. We have wet batteries now, but they’ll develop better ones.