Extraordinary Capacitance and Stability of Carbon Electrode for Electrochemical Capacitors

To further improve the energy density and reliability of carbon based electrochemical capacitors, such as electric double-layer capacitors and lithium ion capacitors, it is necessary to increase both the electric double layer capacitance and stability of the porous carbon electrodes used in the capacitors. Not only the specific surface area and pore size, but also the pore shape and pore size distribution, and the analytical methods to properly evaluate the pore structure should be considered when improving the capacitance. In the case of the high stability to high voltage charging, it is important to design and control the three-dimensional structure of the electrode as well as the crystal structure and crystallinity of the carbon. In this review, some advanced examples of the recent research on these topics will be discussed.