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

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 m(2) g(-1)), hierarchical interconnected pores, moderate pore volume (1.78 cm(3) 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.