Everyone knows what batteries are and how they’re used, even if most people don’t fully understand the underlying principles or the specifics of different battery chemistries and technologies.
As a battery is used, the chemicals that store the energy get used up, and eventually, the battery is "dead" or fully discharged. In rechargeable batteries like the lithium-ion ones in phones and laptops, the chemical reactions can run in reverse. When you charge the battery, energy from the charger restores the chemicals to their original state so the battery can be used again. This process can usually be repeated hundreds or even thousands of times before the battery starts to wear out.
Supercapacitors, though they work differently from batteries, are just as fascinating. Instead of storing energy through chemical reactions, they rely on physical processes. Their two main components are the electrodes—made from materials with a very high surface area (like activated carbon, or Skeleton's proprietary Curved Graphene)—and the electrolyte, which provides mobile ions that migrate to the electrodes during charging, forming an electric double-layer. This allows rapid charge and discharge without chemical degradation.
Supercapacitors are high-power storage devices, whereas batteries are generally high-energy devices. Generally, limited energy density is the only weakness of supercapacitors. However, the distinction between power and energy is key to understanding which technology is most suitable for a specific application.
Energy (Capacity) = How much total work can be done
→ Measured in joules (J) or watt-hours (Wh)
→ Example: A car's fuel tank holds 50 liters of fuel → that’s its energy capacity.
Batteries power your cell phone, electric cars, laptops, and many other everyday items.
Power = How fast you can use the energy
→ Measured in watts (W) or kilowatts (kW)
→ Example: A sports car can burn fuel quickly to accelerate fast, while a regular car burns it more slowly.
Supercapacitors power applications like regenerative braking in buses and trams, peak shaving in AI data centers, and provide immediate reactive power for power grids.
As we often like to say at Skeleton, we are not in the kWh business (high energy → batteries), we're in the MWs business (high power → supercapacitors). To put it even more simply:
- Your application needs long runtime? Use batteries.
- Your application needs instant power, quick charging, and durability? Use supercapacitors.
What happens when you need both energy AND power? In some cases, the best solution is not choosing one or the other—batteries or supercapacitors—but using both. Batteries and supercapacitors are complementary technologies and can be used in a hybrid system, where batteries provide long-term energy, and supercapacitors handle the high peaks of power.
Supercapacitor jelly rolls at Skeleton's manufacturing facility.
Welcome to Supercapacitors 101, a comprehensive blog series that explains the science, technology, and innovation behind supercapacitor energy storage.
Whether you’re an energy enthusiast or simply curious about the future of energy storage, this series will equip you with the knowledge to understand and appreciate the potential of supercapacitors, as well as the applications where supercapacitors shine.
Upcoming Supercapacitors 101 Series blogs:
- Introduction to supercapacitors
- Maintenance and lifespan of supercapacitors
- Supercapacitors vs. batteries
- Types of supercapacitors
- Supercapacitor capacitance: What are Farads?
- Supercapacitor voltage
- Benefits and limitations of supercapacitors
- Supercapacitors in extreme conditions
- The role of internal resistance in supercapacitor performance
- Sizing and selection of supercapacitors
- How are supercapacitors made?
- Future trends in supercapacitor technology
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