“…In order to be able to use these environmentally friendly and renewable sources of energy in the long term, new and effective energy storage systems must be developed [10]. Supercapacitors (also known as electrochemical capacitors or ultracapacitors) are a type of energy storage device that is attracting more and more attention because they can be charged and discharged C 2020, 6, 17; doi:10.3390/c6020017 www.mdpi.com/journal/carbon C 2020, 6, 17 2 of 12 very fast, have a very high power density (<10,000 W•kg −1 ), require little maintenance and have a long life of over 1 million charge and discharge cycles [1,2,11]. For the production of such supercapacitors, carbon materials are used as electrodes, since they are chemically and thermally stable and easy to process.…”