Is it only a matter of time before ...

... we have the flux capacitor?

Electrostatic capacitors.

Electrostatic capacitors store charge on the surface of two conducting plates separated by an insulating layer. Their advantage is that they can store and release energy much faster than batteries.

That makes them ideal candidates to replace batteries in devices that require speedy discharge of power, such as electric cars. However, electric capacitors can hold only limited charge. Supercapacitors that store charge chemically as well as electrically have greater capacities, but perform only as well as the best batteries.

Now a prototype capacitor has been made that manages to store power as densely as a supercapacitor, but deliver it at speeds comparable with electrostatic capacitors.