Supercapacitor vs Capacitor: What Is The Difference?

In the realm of energy storage, capacitors and supercapacitors play pivotal roles. While both devices store electrical energy, they are not created equal when it comes to design, functionality, and performance. In this article, you are invited to dive into the differences between capacitors and supercapacitors, exploring their energy storage mechanisms, charge-discharge rates, energy density, cycle life, power density, application focus, and future outlook.

Capacitors and Supercapacitors: An Overview

Capacitors, known for their simplicity and reliability, have long been the go-to choice for energy storage in many applications. These devices consist of two conductive plates, or electrodes, separated by a dielectric material. When a voltage is applied, charge accumulates on the plates, creating an electric field. Capacitors store energy in the electric field that forms between the plates, with the amount of energy stored determined by the capacitance value.

Capacitors find wide-ranging applications in many different industries. While they are commonly used for energy storage, capacitors also play a key role in voltage regulation, smoothing out voltage fluctuations and providing stable power supply to electronic components.

In electronic circuits, capacitors are used for filtering and for removing noise or unwanted signals from the system. They can also act as timing elements in oscillators and timers, controlling the rate of electrical pulses.

In audio systems, capacitors are employed for coupling and decoupling, allowing the transfer of audio signals while blocking DC components. They are also utilized in motor starting and run capacitors, aiding the operation of electric motors. Additionally, capacitors have applications in lighting systems, power supplies, telecommunications, automotive electronics, and renewable energy systems.

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Supercapacitors, also known as ultracapacitors or electrochemical capacitors, represent a significant advancement in energy storage technology. They employ a different energy storage mechanism compared to traditional capacitors. Supercapacitors consist of two high-surface-area electrodes, typically made of activated carbon or conducting polymers, immersed in an electrolyte solution. This unique design allows for energy storage in both electrostatic fields, similar to capacitors, and through reversible electrochemical reactions at the electrode-electrolyte interface, known as pseudocapacitance.

Much like traditional capacitors, supercapacitors can also be widely used across numerous applications, from electric vehicle (EVs) charging, to renewable energy systems, medical devices and electronic consumer goods.

Core Differences Between Capacitors and Supercapacitors

  1. Energy Storage

The fundamental difference between capacitors and supercapacitors lies in their energy storage mechanisms. Capacitors store energy electrostatically, relying solely on the electric field formed between the plates. In contrast, supercapacitors combine electrostatic storage with pseudocapacitance, which occurs due to reversible Faradaic reactions at the electrode-electrolyte interface. This unique combination allows supercapacitors to store significantly more energy compared to traditional capacitors.

  1. Charge and Discharge Rates

Another key distinction is the charge and discharge rates of capacitors vs supercapacitors. Capacitors charge and discharge almost instantaneously, as the energy transfer occurs through the electric field. However, their energy release is relatively slow compared to supercapacitors. Supercapacitors, on the other hand, excel in rapid charge and discharge rates, enabling quick energy delivery for applications that require bursts of power or frequent cycling.

  1. Energy Density

When it comes to energy density, capacitors and supercapacitors come from completely different worlds. Capacitors typically have lower energy density, meaning they can store less energy per unit compared to supercapacitors. This limitation comes from the larger separation between electrodes in capacitors, which restricts the amount of energy that can be stored. In contrast, supercapacitors offer higher energy density due to their unique electrode design and the incorporation of pseudocapacitance.

  1. Cycle Life

Cycle life refers to the number of charge-discharge cycles a device can undergo before its performance degrades significantly. Capacitors generally have a high cycle life, with some capacitors capable of enduring millions of cycles without significant capacity loss. However, supercapacitors surpass traditional capacitors in this aspect. With their robust electrode materials and electrochemical reactions, supercapacitors can endure hundreds of thousands to millions of cycles while maintaining their performance.

  1. Power Density

Power density is a measure of how quickly a device can deliver power. Supercapacitors shine in this area due to their ability to deliver high bursts of power. Their rapid charge and discharge rates, combined with low internal resistance, enable supercapacitors to meet the demands of applications requiring quick energy delivery. Capacitors, although capable of fast charging, do not match the power density of supercapacitors.

  1. Applications

Capacitors find wide application in electronic circuits, filtering, voltage regulation, and energy storage in low-power systems. They are suitable for applications that require energy storage with relatively low power requirements. Conversely, supercapacitors, with their high power density and rapid energy transfer capabilities, excel in various fields. Presently, supercapacitors are predominantly used in electric vehicles, renewable energy systems, regenerative braking, grid stabilization, aerospace systems, and other high-power-demand applications.


In conclusion, are supercapacitors better than capacitors? The answer heavily depends on specific application and requirements. Supercapacitors offer higher energy density, faster charge and discharge rates, and longer cycle life compared to traditional capacitors. They excel in applications that demand quick bursts of power and frequent cycling. However, supercapacitors have lower energy storage capacity compared to batteries and can be more expensive.

Capacitors, on the other hand, are reliable, cost-effective, and widely used for energy storage in various electronic circuits. They are suitable for applications with lower power requirements and where long-term energy storage is not a primary concern.

Ultimately, the choice between supercapacitors and capacitors depends on your operation’s specific needs, with balancing factors like power density, energy density, cost, and cycle life.

It is important to keep in mind that the field of energy storage continues to evolve, with ongoing research and development focused on improving both capacitors and supercapacitors. Advancements in materials, electrode design, and electrolyte formulations offer exciting prospects for enhancing energy storage capabilities, increasing energy density, and expanding the range of applications. As technologies continue to mature, we can anticipate further integration of capacitors and supercapacitors in various industries, perpetually revolutionizing energy storage solutions.

 At FastCap, we design the best supercapacitors to fit your operations. Get in touch with us today and let's explore how we can support you to save money, while delivering optimum performance. 

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