Very high energy-density capacitors, typically measured in Farads.
Supercapacitors are also called electric double-layer capacitors (EDLC) or ultracapacitors. Their capacitance per unit volume is far higher than other capacitor technologies, like aluminum electrolytic. Typical supercapacitors are measured in Farads. Supercapacitors are typically used for energy storage applications. As compared to batteries, they can endure more charge cycles and higher charge/discharge currents, but they also hold far less energy per unit volume than most battery technologies.