Peter Sobolev/

Supercapacitors have been around since the 1950s, but only in recent years has their potential become apparent. Let’s take a look at these computer components that store energy just like batteries, but use completely different principles.

What is a capacitor?

Before we get to supercapacitors, it’s worth quickly explaining what a supercapacitor is. condenser normal to help demonstrate what makes supercapacitors special. If you have ever looked at the motherboard of a computer either Virtually any circuit board will have seen these electronic components.

Several supercapacitors on a circuit board.
Marko Aliaksandr/

A capacitor stores electricity as a static electric field . This is the same thing that happens when you walk on a carpet in your socks and build up an electrical charge, only to discharge it when you touch a door handle. You were acting like a capacitor!

Inside a typical capacitor, you’ll find two conductors separated by an insulating material. Positive charge accumulates on one conductor and negative charge on the other. Therefore, there is an electrostatic field between the two plates. There are many different ways to design a capacitor, but they all have the basic components of two charging plates and an insulator (dielectric). The insulator can be air, ceramic, glass, plastic film. liquid, or anything else that is bad at conducting electricity.

Interior of a condenser with annotations.

Capacitors have many uses in electronics. In computers and other digital systems, they make sure that information is not lost if there is a momentary loss of power. They also act as filters to clean electrical surges that could otherwise damage sensitive electronic components.

How Capacitors and Batteries Differ

Capacitors and batteries are similar in that they can store electrical energy and then release it when needed. The big difference is that capacitors store energy as an electrostatic field, while the batteries they use a chemical reaction to store and then release energy.

Inside a battery there are two terminals (anode and cathode) with an electrolyte between them. An electrolyte is a substance (usually a liquid) that contains ions. Ions are atoms or molecules with an electrical charge.

An annotated illustration of the structure and contents of a lithium-ion battery.

There is also a separator inside the electrolyte that only allows ions to pass through it. When you charge the battery, the ions move from one side of the separator to the other. When you discharge the battery, the opposite happens. The movement of ions chemically stores electricity or converts that stored chemical energy into electrical current.

Capacitor vs Supercapacitor

Supercapacitors are also known as ultracapacitors either capacitors double layer . The key difference between supercapacitors and regular capacitors is the capacitance. That just means that supercapacitors can store a much larger electric field than normal capacitors.

In this diagram, you can see another big difference when it comes to supercapacitors. Like a battery (and unlike a traditional capacitor), a supercapacitor has an electrolyte. This means that it uses electrostatic and electrochemical storage principles to hold an electrical charge.

Schematic illustration of the structure and content of a supercapacitor.
Fouad A. Saad/

This is an oversimplification, and the really technical aspects of it would take much longer to explain. The most important thing to know about supercapacitors is that they offer the same general characteristics as capacitors, but can provide many times more energy storage and delivery than the classic design.

The pros and cons of supercapacitors

Supercapacitors offer many advantages over, for example, lithium-ion batteries. Supercapacitors can be charged much faster than batteries. The electrochemical process creates heat, so the charging should be done at a safe pace to avoid catastrophic battery failure. Supercapacitors can also give up their stored energy much faster than an electrochemical battery, for the same reason. If the battery discharges too quickly, it can also lead to catastrophic failure.

Supercapacitors are also much more durable than batteries, particularly lithium-ion batteries. As the batteries found in phones, laptops, and electric cars begin to wear down after a few hundred charge cycles, supercapacitors can be charged and emptied more than a million times without degradation. The same goes for the voltage delivery. A 12V battery can only provide 11.4V in a few years, but a supercapacitor will provide the same voltage after more than a decade of use.

The biggest drawback compared to lithium-ion batteries is that supercapacitors cannot discharge their stored energy as slowly as a lithium-ion battery, making them unsuitable for applications where a device must spend long periods of time without charging.

So as things stand at the time of this writing, supercapacitors are not a direct replacement for lithium-ion batteries or other battery technologies, but there are a growing number of jobs that supercapacitors are perfect for.

supercapacitor products

You’ve probably used products that contain supercapacitors and didn’t even know it. The first supercapacitors were created in the 1950s by a General Electric engineer named Howard Becker. In 1978, NEC coined the name “supercapacitor” and used the device as a form of backup power for computer memory.

Today, you’ll find them at laptops GPS units, handheld computers, camera flashes, and many other electronic devices. The Coleman FlashCell used a supercapacitor instead of a battery. This meant that it ran for half the time of a traditional battery-powered model, but charged in 90 seconds instead of hours.

Similarly, the S-Pen in the Samsung GalaxyNote 9 used a supercapacitor to power the wireless functions of the stylus. The power would run out in a few minutes of heavy use or after 30 seconds of waiting time, but it only takes 40 seconds to fill it up again.

Supercapacitors are also finding a home in the world of hybrid vehicles and electrical . They are perfect for capturing and releasing regenerative braking power, which is a short-term dynamic load. Vehicles such as public transport buses or trams are also suitable for supercapacitors. They just need enough power to get to the next stop, where they’ll charge up again in seconds or minutes. Since supercapacitors don’t actually wear out, this fixed transit cycle makes a lot of sense for the technology.

Are supercapacitors the future of energy storage?

With the way supercapacitor research is progressing, it seems likely that one day we will have supercapacitor batteries. These would be devices that have the durability and speed of supercapacitors, but with the energy density and long run time of batteries. In 2016, scientists at the University of Central Florida created a prototype flexible supercapacitor with a higher energy density than current supercapacitors and a 30,000 charge cycle without degradation.

New nanoscale materials and experiments with graphene point to the possibility that supercapacitors with much higher energy densities are possible. Even if they never quite match up to lithium-ion batteries, a usable amount of charge, coupled with a quick recharge time, could put them in places where batteries currently fill a role.

On the other hand, there are other technologies that compete with supercapacitors. The most important of which is the legendary solid-state battery, and recently traditional graphene-infused lithium-ion batteries have also shown promise. Whatever the technology fast charging lasting and energy dense that wins the race, we will all be winners.

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