Electric aircraft
Ultracapacitors
### Ultracapacitors

An [ultracapacitor](/wiki/Ultracapacitor "Ultracapacitor") is a hybrid electrochemical energy storage system bridging batteries and capacitors, and has some advantages over batteries in being able to charge and discharge much faster with higher peak currents, while not being as limited in the number of charge\-discharge cycles, as the reaction is not just chemical but also electrical.

Their energy density, typically around 5 Wh/kg, is however well below that of batteries, and they are considerably more expensive, even when their longer lifespan is factored in.


How many charge-discharge cycles can an ultracapacitor withstand?