A battle as old as the technologies themselves: ultracapacitors and batteries rule the energy storage industry, fighting for a place at the top. Batteries, as the older and more established technology, wear the crown, but ultracapacitors have taken huge technological leaps forward in the past decade, and are now closing in and overtaking batteries in effectiveness in many areas of energy storage.

Ultracapacitors and batteries differ in one significant way: ultracapacitors store energy in an electric field and batteries store energy in a chemical reaction. Now, if you just need to power your flashlight, you can buy a set of Alkaline batteries and go on your merry, well-lit, way. But if your application requires something more sophisticated, it's vital to understand the benefits of each technology.

Ultracapacitors are what's known as fast energy storage and:

  • have high power density, meaning they can provide very high currents
  • charge and discharge very quickly
  • have a lifetime of over 1 million charge-discharge cycles
  • have very low internal resistance and work close to 100% efficiency
  • are significantly lighter than batteries
  • have high tolerance for extreme temperatures
  • don’t contain harmful chemicals or toxic metals.


Batteries are known as slow energy storage and:

  • have high energy density, meaning they can operate for a long time
  • charge and discharge slowly
  • usually have a lifetime of about 2000-3000 charge-discharge cycles
  • operate poorly in very cold or warm temperatures
  • contain toxic and environmentally harmful chemicals. 


Batteries and ultracaps both have their uses. This infographic is meant to give you a basic understanding on the technologies behind ultracapacitors and the most popular battery types, and provide you with the knowledge to make the decision on what's best for your needs.

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Skeleton Technologies ultracapacitors supercapacitors batteries comparison