Final answer:
A capacitor stores electric energy as electrical potential energy in the form of an electric field and can maintain a voltage across its plates once charged.
Step-by-step explanation:
The circuit element that stores voltage is a capacitor. A capacitor is an electrical component that stores electric energy in an electric field. It is composed of two conductive plates separated by an insulating material called a dielectric.
When a voltage is applied across the plates, an electric field develops across the dielectric, causing positive charge to accumulate on one plate and negative charge on the other.
This ability to store electrical energy distinguishes the capacitor from other circuit elements like resistors, which dissipate energy as heat, and inductors, which store energy in a magnetic field.
It is important to note that capacitors do not actually 'store voltage' but instead store electrical potential energy; however, they can maintain a voltage across their plates once charged.