Electrochemical double layer capacitors: What is next beyond the corner?

This review summarizes some recent developments achieved in the fundamental understanding of ion confinement in microporous carbon supercapacitor electrodes. Combined with computational simulations, these advanced techniques provided new insights into the charge storage mechanism, providing guidelines for designing improved porous carbon structures with high-energy density. Also, innovative electrolytes have recently been proposed by introducing some redox-active moieties into electrolyte anions/cations, called biredox electrolytes, that combines redox contribution to double capacitance. This approach opens up new opportunities to develop high-energy supercapacitors and a new field of biredox electrolytes.