Interconnected Frameworks with a Sandwiched Porous Carbon Layer/Graphene Hybrids for Supercapacitors with High Gravimetric and Volumetric Performances

Abstract

A facile approach to synthesize porous disordered carbon layers as energy storage units coating on graphene sheets to form interconnected frameworks by one‐step pyrolysis of the mixture of graphene oxide/polyaniline and KOH is presented. As effective energy storage units, these porous carbon layers play an important role in enhancing the electrochemical performances. The obtained porous carbon material exhibits a high specific surface area (2927 m2 g−1), hierarchical interconnected pores, moderate pore volume (1.78 cm3 g−1), short ion diffusion paths, and a high nitrogen level (6 at%). It displays both unparalleled gravimetric (481 F g−1) and outstanding volumetric capacitance (212 F cm−3) in an aqueous electrolyte. More importantly, the assembled symmetrical supercapacitor delivers not only high gravimetric (25.7 Wh kg−1 based on total mass of electroactive materials) but also high volumetric energy densities (11.3 Wh L−1) in an aqueous electrolyte. Furthermore, the assembled asymmetric supercapacitor yields a maximum energy density up to 88 Wh kg−1, which is, to the best of our knowledge, the highest value so far reported for carbon//MnO2 asymmetric supercapacitors in aqueous electrolytes. Therefore, this novel carbon material holds great promise for potential applications in energy‐related technological fields.