Charging a capacitor using a switch from a voltage source means only 1/2 the energy is stored on the capacitor.
The other half of the energy is dissipated as heat in the source and switch resistance. It makes no difference how low the resistance, half the energy will be lost.
To avoid this. a resonant charging technique can be used. which will transfer most of the energy to the capacitor, minus only the loss in the inductor, diode, and source resistance.
This also allows charging the...