Accumulating electricity for later use has always been one of the biggest problems in electrical engineering.
It can be done mechanically, in the form of kinetic energy, by rotating a large mass placed on the periphery of a disk or in the form of potential energy, raising a mass at a suitable height, releasing it when necessary.
It can be done chemically by exploiting the accumulation or release of electrons in an oxidation-reduction process such as lead batteries, nickel-cadmium or lithium-ion batteries.
It can be done electrostatically by exploiting the accumulation or release of electrons in particular insulating materials as in the most recent ultracapacitors.
Knowing the multiple technologies and how to use them allows us to choose the most appropriate in each specific application.