Supercapacitors are divided into three families, based on electrode design:
- Double-layer capacitors – with carbon electrodes or derivates with much higher electrostatic double-layer capacitance than electrochemical pseudocapacitance
- Pseudocapacitors – with metal oxide or conducting polymer electrodes with a high amount of electrochemical pseudocapacitance
- Hybrid capacitors – capacitors with asymmetric electrodes, one of which exhibits mostly electrostatic and the other mostly electrochemical capacitance, such as lithium-ion capacitors Supercapacitors bridge the gap between conventional capacitors and rechargeable batteries. They store the most energy per unit volume or mass (energy density) among capacitors. They support up to 10,000 farads/1.2 volt, up to 10,000 times that of electrolytic capacitors, but deliver or accept less than half as much energy per unit time (power density). By contrast, while supercapacitors have energy densities that are approximately 10% of conventional batteries, their power density is generally 10 to 100 times greater. This results in much shorter charge/discharge cycles than batteries. Additionally, they will tolerate many more charge and discharge cycles than batteries.
Applications: frequency or voltage regulation, mobility