Spatial charge storage on the nitrogen-doped graphene for ultrafast supercapacitors with high EDLC capacity

Abstract

The limited specific surface area of carbon substance restricts the raise of the electrochemistry double layer capacitance (EDLC). If the charge storage location could be extended from surface to space, the EDLC of carbon materials can be greatly improved. Here, an original spatial charge storage mechanism according to the counterion effect from Fe (CN)6 3− ions bridged by nitrogenous groups is proposed, which can provide additionally spatial charge storage for EDLCs. More importantly, the graphene designed based on this structure can achieve a high storage capacity of 334 F g−1 at 0.5 A g−1 (the rate retention is 64% at 50 A g−1) in 6 M KOH electrolyte, much higher than the sample without space charge storage effect (from 270 to 160 F g−1). This novel strategy for the design of graphene with multiple spatial active sites can be extended to other carbon materials, which can propose a new idea for the development of carbon materials in the field of energy storage.