Editing Energy storage (section)

==== Supercapacitor ====
[[File:Expo 2010 Electric Bus.jpg|thumb|One of a fleet of [[capa vehicle|electric capabuses]] powered by supercapacitors, at a quick-charge station-bus stop, in service during [[Expo 2010|Expo 2010 Shanghai China]]. Charging rails can be seen suspended over the bus.]]
{{main|Supercapacitor}}

[[Supercapacitor]]s, also called electric double-layer capacitors (EDLC) or ultracapacitors, are a family of [[electrochemical capacitor]]s<ref name="Conway" /> that do not have conventional solid [[dielectric]]s. [[Capacitance]] is determined by two storage principles, double-layer capacitance and [[pseudocapacitance]].<ref name="Halper" /><ref name="Frackowiak1" />

Supercapacitors bridge the gap between conventional capacitors and [[Rechargeable battery|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,<ref name="Elton" /> up to 10,000 times that of [[electrolytic capacitor]]s, but deliver or accept less than half as much power per unit time ([[power density]]).<ref name="Conway" />

While supercapacitors have specific energy and energy densities that are approximately 10% of batteries, their power density is generally 10 to 100 times greater. This results in much shorter charge/discharge cycles. Also, they tolerate many more charge-discharge cycles than batteries.

Supercapacitors have many applications, including:
* Low supply current for memory backup in [[static random-access memory]] (SRAM)
* Power for cars, buses, trains, cranes and elevators, including energy recovery from braking, short-term energy storage and burst-mode power delivery