What are the characteristics and principles of supercapacitors?

Summary:The supercapacitor is a new type of component that stores energy through the int...

The supercapacitor is a new type of component that stores energy through the interface double layer formed between the electrode and the electrolyte. When the electrode is in contact with the electrolyte, due to the Coulomb force, intermolecular force and interatomic force, the solid-liquid interface has a stable double-layer charge with opposite signs, which is called the interface double layer. Think of the electric double layer supercapacitor as two inactive porous plates suspended in the electrolyte, and the voltage is applied to the two plates. The potential applied to the positive plate attracts negative ions in the electrolyte, and the negative plate attracts positive ions, thereby forming an electric double layer capacitor on the surface of the two electrodes. Electric double layer capacitors can be divided into carbon electrode double-layer supercapacitors, metal oxide electrode supercapacitors and organic polymer electrode supercapacitors according to different electrode materials


Compared with batteries and traditional physical capacitors, the characteristics of super capacitors are mainly reflected in:
(1) High power density. It can reach 102 ~ 104 W / kg, which is much higher than the power density of the battery.
(2) Long cycle life. After a few seconds of high-speed deep charge and discharge cycles of 500,000 to 1 million times, the characteristics of the supercapacitor change little, and the capacity and internal resistance are only reduced by 10% to 20%.
(3) Wide working temperature limit. Since the adsorption and desorption speeds of ions in supercapacitors do not change much at low temperatures, their capacity changes are much smaller than those of batteries. The operating temperature range of commercial supercapacitors can reach -40 ℃ ~ + 80 ℃.
(4) Maintenance free. Supercapacitors have high charge and discharge efficiency, have a certain tolerance to overcharge and overdischarge, can be repeatedly charged and discharged stably, and theoretically do not require maintenance.
(5) Green and environmental protection. Supercapacitors do not use heavy metals and other harmful chemicals in the production process, and have a long life. Therefore, they are a new type of green environmental protection power supply.