Both batteries and capacitors are electronic devices capable of storing electrical charge and they seem awfully similar as they both release electrical energy. However, the way they do it vary dramatically. While a battery stores potential energy in the chemical form, a capacitor stores its potential energy in an electrostatic field. In simple terms, batteries store and distribute energy in a linear form – like a constant electrical flow. Capacitors, on the other hand, distribute energy in short bursts. A capacitor stores energy directly onto the plates which makes charging/discharging a bit faster than batteries. However, batteries are capable of regaining their stored energy much efficiently and for a longer duration than capacitors.

Comparison between the two:

Battery

A battery stores its potential energy in the form of chemical energy.

It has a better energy density which means more energy per volume can be stored. It is basically a DC component.

Charge/discharge rate is relatively slower than capacitors.

Charges are not separated in a battery.

Battery runs for a longer time.

Capacitor

A capacitor uses electrostatic field to store electrical energy.

It has a comparatively low energy density than a battery. It is ideally used for AC applications.

Charge/discharge rate is usually faster than a battery because it stores energy directly onto the plates. Electrons are pre-stocked in capacitors.

Capacitors discharge almost instantaneously.