Duh, the dielectric is everything in a capacitor.
The thinner the dielectric the more plates can be used in a given space.
If they haven't determined the 'functionality and strength' of the dielectric, they haven't done anything.
Yes, the dielectric IS everything that really matters, and the measure of it is the dielectric constant of the material (for storage of energy in the polarization of the its molecules) and its insulating properties, which determine the maximum voltage that it can support without breaking down.
But the 5-minute charge is a joke, unless you have your own nuclear power plant. Others have offered some calculations and estimates of what it would require, so I don’t need to pile on.