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Railway shipment Position Cut-off A supercapacitor is a very large capacity capacitor with a capacitance of up to several thousand Farads. According to the principle of the capacitor, the capacitance depends on the distance between the electrodes and the surface area of the electrode. In order...
Railway shipment Position Cut-off
A supercapacitor is a very large capacity capacitor with a capacitance of up to several thousand Farads. According to the principle of the capacitor, the capacitance depends on the distance between the electrodes and the surface area of the electrode. In order to obtain such a large capacitance, the distance between the electrodes of the supercapacitor should be reduced as much as possible, and the surface area of the electrode should be increased. For this reason, the principle of electric double layer and porous magnetization of activated carbon are adopted. electrode.
When a supercapacitor electric double layer dielectric applies a voltage on two electrodes of a capacitor, a charge opposite to the polarity of the charge carried by the electrode is generated at a dielectric interface close to the electrode and is bound to the interface of the medium to form a capacitor. Two electrodes. It is obvious that the distance between the two electrodes is very small, only a few nm. At the same time, the activated carbon porous electrode can obtain a very large electrode surface area, which can reach 200 m2 / g. Therefore, the supercapacitor of this structure has a large electric capacity and can store a large amount of electrostatic energy. In terms of energy storage, this characteristic of supercapacitors is between traditional capacitors and batteries. When the potential between the two electrode plates is lower than the redox electrode potential of the electrolyte, the charge at the interface of the electrolyte will not leave the electrolyte, and the supercapacitor is in a normal working state (usually below 3V), if the voltage at the two ends of the capacitor exceeds The redox electrode potential of the electrolyte, then the electrolyte will decompose and be in an abnormal state. As the supercapacitor discharges, the charge on the positive and negative plates is vented by the external circuit, and the charge response at the electrolyte interface is reduced. It can be seen that the charging and discharging process of the supercapacitor is always a physical process, and there is no chemical reaction, so the performance is stable, unlike the battery using the chemical reaction.