What is Supercapacitor: Definition and 22 Discussions

A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor with a capacitance value much higher than other capacitors, but with lower voltage limits, that bridges the gap between electrolytic capacitors and rechargeable batteries. It typically stores 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, can accept and deliver charge much faster than batteries, and tolerates many more charge and discharge cycles than rechargeable batteries.Supercapacitors are used in applications requiring many rapid charge/discharge cycles, rather than long-term compact energy storage — in automobiles, buses, trains, cranes and elevators, where they are used for regenerative braking, short-term energy storage, or burst-mode power delivery. Smaller units are used as power backup for static random-access memory (SRAM).
Unlike ordinary capacitors, supercapacitors do not use the conventional solid dielectric, but rather, they use electrostatic double-layer capacitance and electrochemical pseudocapacitance, both of which contribute to the total capacitance of the capacitor, with a few differences:

Electrostatic double-layer capacitors (EDLCs) use carbon electrodes or derivatives with much higher electrostatic double-layer capacitance than electrochemical pseudocapacitance, achieving separation of charge in a Helmholtz double layer at the interface between the surface of a conductive electrode and an electrolyte. The separation of charge is of the order of a few ångströms (0.3–0.8 nm), much smaller than in a conventional capacitor.
Electrochemical pseudocapacitors use metal oxide or conducting polymer electrodes with a high amount of electrochemical pseudocapacitance additional to the double-layer capacitance. Pseudocapacitance is achieved by Faradaic electron charge-transfer with redox reactions, intercalation or electrosorption.
Hybrid capacitors, such as the lithium-ion capacitor, use electrodes with differing characteristics: one exhibiting mostly electrostatic capacitance and the other mostly electrochemical capacitance.The electrolyte forms an ionic conductive connection between the two electrodes which distinguishes them from conventional electrolytic capacitors where a dielectric layer always exists, and the so-called electrolyte, e.g., MnO2 or conducting polymer, is in fact part of the second electrode (the cathode, or more correctly the positive electrode). Supercapacitors are polarized by design with asymmetric electrodes, or, for symmetric electrodes, by a potential applied during manufacture.

View More On Wikipedia.org
  1. Milo08821

    Making a handcranked flashlight with a supercapcitor

    TL;DR Summary: I want to make a handcranked flashight with a supercapacitor, I need some help and thoughts about what type of capacitor do i need and how many to make suppercapacitor. the dc motor im going to use is a geared motor wich is; DC Gear Motor 12V 250RPM- SGM25-370 Specifications...
  2. Fred404

    Supercapacitor dragster project

    Hi all! I’m currently working on a project for which students will have to build a supercapacitor based dragster. I saw here and there some videos on how it works but it’s too general to give me hints about components choice. So here I am with my questions, hoping that I’ll get enough answers...
  3. E

    Could you show me a super capacitor's charging circuit? :(

    What is the fastest circuit to charge a supercapacitor?? could you show me??
  4. D

    What's all this supercapacitor stuff anyhow?

    Anyone on this site that happens to be a supercapacitor expert? I'm looking for a real supercap genius. I see a lot of "super capacitor" parts for purchase online from various sources like Digikey and Mouser but what I don't see is an informative guide on how to figure out what type is the...
  5. D

    Which supercapacitor range is needed to run a 48V DC motor?

    I'm doing a project where I need to hand power for dc motor (12V or 24V) and charge a super capacitor, and then use it to drive another 48V dc motor. I want to know which Super capacitor will be suitable? Please give suggestions for Super capacitor specifications for both 12V and 24V that will...
  6. P

    Do Joule Thief's Work With Supercapacitors

    I have a supercapcitor to power some of my small projects. The only problem is that the voltage drops gradually, unlike a lithium ion battery, in which the voltage is mostly stable throughout. My boost converter that I am using to boost the voltage up to 5 volts, stops working with an input...
  7. P

    Charging Super Capacitor w/Buck Converter: Max Voltage Draw?

    If I am charging a super capacitor with buck converter, that is a 1 amp, 1-18 volt output, and the capacitor is rated for 2.5 volts, how do I stop the buck converter from feeding it more than 2.5 volts? When I attach the capacitor to my digital power supply, it starts charging, and the voltage...
  8. B

    Electrical DIY supercapacitor fabrication

    Greetings. I started a new project, I am trying to establish a basic fabrication method so I can test different common household electrolytes when placed between two activated carbon electrode. https://drive.google.com/file/d/0BwO5zSDThdxFazQyeHM5ZFVEdDg/view?usp=sharing The main problem I am...
  9. B

    Can a 6M NaCl Solution Be Used as an Electrolyte for a Low-Tech Supercapacitor?

    Hey guys, Currently I am trying to build a low tech super capacitor based on the working the principle. Right now I am using a single beaker with two aluminium foil positive and negative electrodes with an electrolyte of 6M NaCl solution. The power source is a new-ish triple-A battery running...
  10. P

    What is the F/cm^2 for a commercial supercapacitor?

    What is the F/cm^2 for a commercially available supercapacitor? Much of the literature is on newer types of carbon, such as graphene, but are commercially available supercapacitors based on activated carbon? http://www.pnas.org/content/suppl/2015/03/22/1420398112.DCSupplemental In this article...
  11. cosmos1226

    Is Charging a 2.7V, 350F Supercapacitor with a 10mA, 20V Source Safe?

    I have supercapcitor 2.7V, 350F. I want to charge it by 0.001mA 20V power source. Is it safe? Thanks you!.
  12. B

    Homemade Supercapacitor Capacitance test --

    Hi all, My friend and I have created a homemade supercapacitor. It can power a LED light and small alarm clock. We charged it up to 1.5 Volts. I was wondering if anyone knew how to find the exact capacitance in Farads, any help will be appreciated. I have added the steps that we have taken in...
  13. S

    Why supercapacitor energy density is so high?

    In battery we have (in ideal) case one electron per atom or three elecrons (in case of aluminum) which flow from anode to cathode.In activaded carbon there should be immensely smaller amount of free electrons than in metals.I do not have exact date for carbon, but for example in Germanium it is...
  14. E

    Graphene supercapacitor production using scotch tape

    I have had a question on my mind for a while now. Would it be possible to make a graphene supercapacitor using the scotch tape method for making graphene? Except unroll the entire roll of tape and cover it in graphite and then press it against another entire roll of scotch tape, peel off and...
  15. Artlav

    Supercapacitor charging voltage?

    Is it safe to charge a supercapacitor from a source with more than it's rated voltage, provided that the voltage across the cap never exceeds the rating? For example, the cap is rated at 2.7V, and i charge it from two AA batteries giving just over 3.2V in open circuit. Once the battery...
  16. S

    Design PWM to cope with supercapacitor and battery(help)

    I need to design an electric circuit which require PWM to let the battery and supercapacitor take turn to supply current to the loads. stage1: battery charge up supercap and supply current to the load stage2: supercap voltage increase to a certain level, battery current is cut, supercap...
  17. Artlav

    Supercapacitor Safety: Read About Currents, Failure Modes & More

    Greetings. Where can i read about safety and failure modes of supercapacitors? What kind of currents would be safe, if not marked? What would happen if that current is exceeded? What would happen if a charged SC gets short-circuited, briefly or for a while? Can anyone help, by...
  18. S

    High voltage supercapacitor is possible?

    Energy density of supercap is equal to square of it`s voltage. Is it possible to join together advantages of supercaps and high voltage capacitors such as Ferroelectric caps? What prevents to use high-k materials in supercaps?
  19. J

    Can Supercapacitors Be Connected Independently to a Power Source?

    I am familiar with changes that occur with capacitance and ESR when you connect supercapacitors in series or in parallel. My question is along those lines, but the answer is elusive to me... From schematics I have seen about supercapacitors imbedded in circuitry, the supercaps always have...
  20. C

    12V 19Ah Motorcycle Battery to Supercapacitor

    The Lead Acid Battery in my H-D '09 FXDF is rated 12V at 19Ah. If I understand the math correctly, I would need a 12V capacitor rated to 5,700F. Is this accurate? 1 F = 1 As/V 1 Ah = 3600 As 19Ah x (3600As/1Ah) = 68,400As (68,400As/12V) x (1F/[1As/V]) = 5,700 F As I understand it...
  21. T

    Battery supercapacitor hybrid design

    hello! i would like to ask for your opinions. i have tried using supercapacitor in my circuit to prolong its battery run-time. I have attached a simple circuit design for your reference. the problem is that the load drains the supercapacitor faster than the battery charging the supercap...