How many joules or watts or how much energy can this theoretical capacitor hold

how many farads, what would the current be and how many volts could it tolerate, how to increase volt tolerance. how to increase charge rate, decrease charge time?

how much surface area would be needed for the electrodes, thinking of hafnium as a electrode and thinking of teflon as a insulator since it has a dielectric strength of 60x10^6, but it melts around 650 degrees. is there something else with a high dielectric strength but higher melting point? any input on these questions is greatly appreciated