Residents do not always have a clear understanding of the differences between traditional batteries and EDLC. Let's try to cover this issue in a simple and understandable language.
The battery always has different electrodes made of different materials. During the discharge, one electrode is oxidized while another is reduced. Due to this, the entire mass of electrodes is involved in the generation of current. Due to the different materials of the electrodes, the battery is usually ready for use immediately after assembly, since voltage can be fixed at its terminals (i.e. potential difference).
Ultracapacitors have electrodes made of the same material. For example, nanoporous coal having a high specific surface is often used in this quality. After assembly, the ultracapacitor has no energy. In order for it to start working, you must first charge, that is, accumulate energy.
Thus, everyone who is going to buy a ultracapacitor should understand that this is not a source of energy, but its storage. The mechanical analog in this case is a spring. When it is stretched, energy appears that can produce work. The EDLC suggests stretching not charges of metal (mechanically), but charges (electrically).
A ultracapacitor cannot be considered a replacement battery. However, the parallel use of one and the other greatly expands the possibilities of our usual technique.