Controllable synthesis of 2D mesoporous nitrogen-doped carbon/graphene nanosheets for high-performance micro-supercapacitors

Graphene-based 2D mesoporous materials have been considered ideal electrode materials for micro-supercapacitors (MSCs). 2D mesoporous nitrogen-doped carbon/graphene (mNC/G) nanosheets were prepared by the solution polymerization of aniline as the carbon and nitrogen precursor, in mixtures of graphene oxide as a guide for the 2D structure and silica nanospheres as a mesopore template. This was followed by leaching with dilute NaOH to remove the silica, freeze drying and carbonization. The nanosheets were formed from the templated mesoporous nitrogen-doped carbon decorating both sides of the graphene sheets. Precise regulation of the mesopore size and optimization of the electrochemical performance of the material were achieved. mNC/G with a pore size of 7 nm (mNC/G-7) had a specific capacitance of 267 F g⁻¹, and quasi-solid-state planar MSCs based on it had a high volumetric capacitance of 21.0 F cm⁻³ and an energy density of 1.9 mWh cm⁻³, indicating the tremendous potential of 2D mNC/G for MSCs.