Supercapacitors are electrochemical capacitors with very high capacitance values, typically much higher than those of conventional capacitors. The term “supercapacitor” was first used in 1974 by Dr. Richard S. Muller of the University of California at Berkeley. Supercapacitors are also known as ultracapacitors or double-layer capacitors (DLCs).
Supercapacitor technology has its roots in research conducted in the late 19th century by Swedish chemist Carl Gassner, who discovered that activated charcoal had unusually high electrical energy storage capacity. In 1957, Russian scientist Leo Beranek published a paper describing Carbon electrodes with high specific surface areas for use in electrochemical capacitors. This work laid the foundation for further development of supercapacitor technology.
In the early 1960s, American scientists Waldo Hanchett and Joel Stern managed to increase the specific surface area of activated charcoal by a factor of 100,000 using an etching process developed by Hanchett. This breakthrough allowed for the production of supercapacitors with extremely high capacitance values. Subsequent research led to the development of other electrode materials with even higher specific surface areas, such as conducting polymers and nanoporous carbon materials. These advances paved the way for modern supercapacitor technology.
Supercapacitors are typically made up of two metal plates separated by an electrolyte material (e.g., ionic liquid or gel). When a voltage is applied across the plates, ions from the electrolyte flow into one plate and electrons flow into the other plate, resulting in a build-up of charge on each plate. This process is reversible, meaning that when the voltage is removed, the ions and electrons will flow back into their respective places and discharge will occur. The amount of charge that can be stored on each plate is determined by its surface area and Faraday’s constant (the amount of charge required to produce one mole