2019 年 62 巻 12 号 p. 698-702
Electrochemical capacitors also called supercapacitors or ultracapacitors are mainly classified into three types : electric double layer capacitors, pseudocapacitors, and asymmetric capacitors assembled with faradic and nonfaradic electrodes. Recently, they have received a great attention as electrical storage devices with high power density and long cycle life compared with secondary batteries, and have been extensively researched and developed. They have played an important role as power sources in various electric devices, regenerating system of vehicles, and so on. Their contribution to leveling output fluctuation of renewable powers is also expected. They would develop more and more as essential power sources in the future. In this article, fundamental principles, characteristics, constituent materials and so on for electrochemical capacitors are described.