This deals with the principle, advantages, limitation and applications of Supercapacitor.

2. A supercapacitor (SC), is a high-
capacity capacitor with a capacitance value much
higher than other capacitors, but with lower voltage
limits
It is also known as ultracapacitor.
The capacitence range is from 100 to 5k Farad.
It can accept and deliver charge much faster than
batteries, and tolerates many more charge and
discharge cycles than rechargeable batteries.

3. A supercapacitor differs from an ordinary capacitor in two different ways.
 Its plates effectively have a much bigger area and the distance between them is
very much smaller, because the separator between them works in a different way to
a conventional dielectric.
In a supercapacitor there is no dielectric as such. Instead, both plates are soaked
in an electrolyte and separated by a very thin insulator.
Working principle of supercapacitors :

4. When the plates are charged up, an opposite charge forms on
either side of the separator, creating what’s called a electric double
layer, maybe just one molecule thick.

5. There are two types of double layer capacitor resulting from different charge
storage mechanisms.
Electrical double-layer capacitor: An EDLC stores energy in the double-
layer at the electrode/electrolyte interface. In this type of capacitor, the
electrode material used for the construction of the cell for the former is
mainly carbon material.
 Electrochemical double layer capacitor or super/pseudo-capacitor:
supercapacitor sustains a Faradic reaction between the electrode and the
electrolyte in a suitable potential window. In this type of supercapacitor the
electrode material consists of either transition metal oxides or mixtures of
carbon and metal oxides/polymers.

6. Advantages of supercapacitor:
 Provide peak power and backup power.
 Extend battery run time and battery life.
 Reduce battery size, weight and cost.
 Enable low/high (-40⁰C to +65⁰C) temperature operation.
 Improve load balancing when used in parallel with a battery.
 Provide energy storage and source balancing when used with energy harvesters
 Eco-friendly.

7. Limitations:
 It can’t be used in AC & high frequency circuits.
 High self discharge.
 Low energy density.
 Supercapacitors are generally restricted to operating voltages in the region of
2.5 - 2.7V
 In order to achieve higher operating voltages for supercapacitors, they can be
placed in series. This reduces the total capacitance.

8. Applications:
 They can primarily be found in applications that require rapid charge and
discharge cycles, such as in automobiles where they are used for regenerative
braking.
 Another common application for supercapacitors is in wind turbines. Here,
very large supercapacitors help to smooth out the intermittent power supplied
by the wind.
 Due to unique storage capability of supercapacitors, it has been widely used in
various applications like electric drives, UPS, electric vehicles, SSD’s, LED
flashlights etc.