Capacitors vs. Supercapacitors

What's the Difference?

Capacitors and supercapacitors are both energy storage devices, but they differ in terms of their energy storage capacity and charging/discharging capabilities. Capacitors store energy by accumulating electric charge on two conductive plates separated by an insulating material, known as a dielectric. They can quickly charge and discharge energy, making them suitable for applications requiring rapid energy transfer. On the other hand, supercapacitors, also known as ultracapacitors, have a much higher energy storage capacity due to their unique electrode materials and electrolytes. They can store and release larger amounts of energy over longer periods, making them ideal for applications that require high power density and longer operational lifetimes.


Energy StorageLowHigh
Charge/Discharge TimeFastVery Fast
Energy DensityLowHigh
Power DensityLowHigh
Operating VoltageLow to HighLow to Moderate
CostLow to ModerateHigh
SizeSmall to LargeSmall to Moderate

Further Detail


Capacitors and supercapacitors are both electronic components used for energy storage, but they differ in several key attributes. While capacitors have been widely used for decades, supercapacitors are a relatively newer technology that offers unique advantages. In this article, we will explore the attributes of both capacitors and supercapacitors, highlighting their differences and applications.


Capacitors are passive electronic components that store and release electrical energy. They consist of two conductive plates separated by a dielectric material. When a voltage is applied across the plates, an electric field is created, causing the accumulation of charge on each plate. The amount of charge stored in a capacitor is directly proportional to the voltage applied and the capacitance value of the component.

Capacitors are known for their ability to store and release energy quickly. They are commonly used in electronic circuits for various purposes, such as smoothing power supply voltages, filtering out noise, and storing energy for short-term backup. Capacitors are available in a wide range of capacitance values, voltage ratings, and form factors, making them versatile for different applications.

One of the key attributes of capacitors is their ability to handle high current surges. They have low equivalent series resistance (ESR), allowing them to discharge energy rapidly. However, capacitors have limited energy storage capacity compared to other energy storage devices, such as batteries. They are also sensitive to temperature variations and have a limited lifespan.

Capacitors are commonly used in electronic devices, including computers, televisions, radios, and power supplies. They are also used in electric vehicles for energy storage and power delivery.


Supercapacitors, also known as ultracapacitors or electric double-layer capacitors (EDLCs), are a type of capacitor that offers significantly higher energy storage capacity compared to traditional capacitors. They store energy through the separation of charge at the interface between an electrode and an electrolyte.

Unlike capacitors, supercapacitors do not rely on a dielectric material for energy storage. Instead, they utilize the phenomenon of electrostatic double-layer capacitance and pseudocapacitance to achieve high capacitance values. This unique design allows supercapacitors to store much larger amounts of energy compared to capacitors.

Supercapacitors have several advantages over capacitors. They have a longer lifespan, with some supercapacitors capable of enduring millions of charge-discharge cycles. They also exhibit a wider operating temperature range and are less affected by temperature variations compared to capacitors. Additionally, supercapacitors have a lower self-discharge rate, meaning they can retain their stored energy for longer periods without significant losses.

Due to their high energy storage capacity, supercapacitors find applications in various fields. They are commonly used in hybrid and electric vehicles for regenerative braking, providing bursts of power during acceleration, and smoothing power supply fluctuations. Supercapacitors are also utilized in renewable energy systems, such as wind and solar power, to store excess energy and deliver it when needed.


When comparing capacitors and supercapacitors, several key attributes differentiate the two:

  • Energy Storage Capacity: Capacitors have relatively low energy storage capacity, typically measured in microfarads (μF) or millifarads (mF). Supercapacitors, on the other hand, offer much higher energy storage capacity, often measured in farads (F) or kilofarads (kF).
  • Power Density: Capacitors have high power density, allowing them to deliver energy quickly. However, supercapacitors have even higher power density, making them ideal for applications requiring rapid energy release.
  • Lifespan: Capacitors have a limited lifespan, typically ranging from thousands to tens of thousands of charge-discharge cycles. Supercapacitors, on the other hand, have a much longer lifespan, often exceeding millions of cycles.
  • Self-Discharge Rate: Capacitors have a higher self-discharge rate, meaning they lose their stored energy more quickly over time. Supercapacitors have a lower self-discharge rate, allowing them to retain their energy for longer periods.
  • Temperature Range: Capacitors are sensitive to temperature variations and may experience performance degradation outside their specified temperature range. Supercapacitors, on the other hand, have a wider operating temperature range and are more resilient to temperature changes.


Capacitors and supercapacitors are both valuable components for energy storage in electronic systems. While capacitors offer quick energy discharge and are widely used in various applications, supercapacitors provide significantly higher energy storage capacity, longer lifespan, and better performance in extreme conditions. The choice between capacitors and supercapacitors depends on the specific requirements of the application, with capacitors being suitable for smaller energy storage needs and supercapacitors being ideal for high-capacity energy storage and rapid energy release.

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