Solution supercapacitor technology

Supercapacitors are also called electric double-layer capacitors. From a structural point of view, they are very similar to electrolytic capacitors. To put it simply, if two electrodes are inserted into the electrolyte and a voltage is applied, the positive and negative ions in the electrolyte will quickly move to the two poles under the action of the electric field, and finally form a compact electrode on the surface of the two electrodes respectively. charge layer, the electric double layer.

The size of the capacitance depends on the size of the electrode surface area and the distance between the two electrodes. The electrode surface area of a traditional capacitor is the flat plate area of the conductor. In order to obtain a larger capacity, the conductor material is usually rolled very long, and sometimes a special organizational structure is used to increase its surface area. At the same time, traditional capacitors use insulating materials to separate its two electrodes, generally plastic films, paper, etc., and these materials are also required to be as thin as possible.

The basic function of the capacitor is charging and discharging, but many circuit phenomena extended from the basic charging and discharging function make the capacitor have more colorful uses. In general electronic circuits, capacitors are commonly used to realize bypass, coupling, filtering, oscillation, phase shift and waveform transformation, etc. These functions are the evolution of charging and discharging functions. According to various characteristics of supercapacitors, it is more used in the field of energy, and is usually used as a battery.

The electrode surface area of a supercapacitor is based on a porous carbon material. The porous structure of the material makes the surface area very large, and the distance between the electrodes of a supercapacitor is determined by the size of the electrolyte ions that are attracted to the charged electrode. This distance is the same as that of a traditional capacitor. The distances achievable with thin film materials are even smaller. This huge surface area, coupled with the very small electrode spacing, makes the supercapacitor have an amazing electrostatic storage capacity compared with traditional capacitors, which is also an important reason why it is dubbed "super".

 Compared with lead-acid batteries, nickel-cadmium batteries, and lithium-ion batteries, supercapacitors have the advantages of energy saving, long service life, safety, environmental protection, wide temperature range, and no need for manual maintenance. Since supercapacitors use physical methods to store energy, one of their most important features is their high power density. We can understand it as charging and discharging quickly and absorbing or releasing extremely high energy instantaneously. Batteries can't do it.

Perhaps everything is imperfect, and supercapacitors are no exception. One of its relatively fatal weaknesses is its low energy density. The so-called energy density refers to the amount of energy stored in a certain space or mass of matter. For example, the AAA rechargeable battery we often use, if its mAh is larger, it means its energy density is higher. It can be said that the lower energy density of supercapacitors compared with lithium-ion batteries limits its application in many fields.