Date: July 2022
What is a Super Capacitor?
Standard capacitors are composed of two metallic plates or electrodes separated by a dielectric substance. When a voltage is applied, electrons accumulate at one of the electrodes, storing the electrical charge.
In the meantime, the dielectric material tucked between the electrodes undergoes a process known as “dielectric polarization,” which contributes to increased capacitance.
Super capacitors operate on the same principles, with the exception that the wedging material is an electrolytic solution rather than a dielectric content. When applied voltage, an “electrical double layer” is formed, which aligns both negative and positive charges along the boundaries of the electrodes and the electrolytic solution.
This location serves as a warehouse for electric charges. Activated carbon is frequently used to increase the size of boundary areas. This is because the capacitance of a super capacitor is proportional to the area of the “electrical double layer.” This activated carbon is a well-known porous material with numerous surface holes that aid in covering a large surface area.
Super capacitors have the same structure as a typical battery for electricity storage due to the electrolytic solution and electrodes. In a battery, chemical reactions occur between the electrolytic solution and the electrodes; however, super capacitors only allow electrons to move between electrodes. Because of these distinctions, the properties of a battery and a super capacitor differ.
What are the benefits of a Super Capacitor?
Charging and discharge times of super capacitors are equivalent to those of conventional capacitors. Considering their low internal resistance, they can obtain significant charge and discharge currents. Batteries can take many hours to fully charge – a cell phone battery is a good example – whereas super capacitors can reach the same charge state in less than two minutes.
The specific energy of a battery or super capacitor is a metric used to evaluate different technologies based on maximum power output divided by total device mass. Super capacitors have a specific power that is 5 to 10 times that of batteries. For example, while Li-ion batteries have a specific power of 1 – 3 kW/kg, a typical super capacitor has a specific power of around 10 kW/kg. This property is particularly important in applications that demand the storage device to release energy in short bursts.
Life Cycle and Safety of a Super capacitor
When treated unfairly, super capacitor batteries are safer than standard batteries. When batteries are short-circuited, they are known to spontaneously combust due to excessive heating; however, super capacitors do not heat up as much due to their low internal resistance.
Super capacitors can be charged and discharged over 15,000 times with minimal degradation, whereas a normal lithium ion battery can only be charged and discharged 300 times or less with the same loss. This makes super capacitors extremely useful in applications requiring frequent energy storage and release.