Sandwich‐type hybrid carbon nanosheets (SCNMM) consisting of graphene and micro/mesoporous carbon layer are fabricated via a double template method using graphene oxide as the shape‐directing agent and SiO2 nanoparticles as the mesoporous guide. The polypyrrole synthesized in situ on the graphene oxide sheets is used as a carbon precursor. The micro/mesoporous strcutures of the SCNMM are created by a carbonization process followed by HF solution etching and KOH treatment. Sulfur is impregnated into the hybrid carbon nanosheets to generate S@SCNMM composites for the cathode materials in Li‐S secondary batteries. The microstructures and electrochemical performance of the as‐prepared samples are investigated in detail. The hybrid carbon nanosheets, which have a thickness of about 10–25 nm, high surface area of 1588 m2 g−1, and broad pore size distribution of 0.8–6.0 nm, are highly interconnected to form a 3D hierarchical structure. The S@SCNMM sample with the sulfur content of 74 wt% exhibits excellent electrochemical performance, including large reversible capacity, good cycling stability and coulombic efficiency, and good rate capability, which is believed to be due to the structure of hybrid carbon materials with hierarchical porous structure, which have large specific surface area and pore volume.

Nitrogen-doped porous graphene/carbon (NPGC) framework electrode materials have been synthesized via chemical activation of graphene oxide/polypyrrole (GOP) composites with KOH. The effects of the mass ratio of KOH/GOP and activation temperature on the electrochemical performance of NPGC have been discussed. It is found that the NPGC prepared by activating GOP (GO : Py ¼ 1 : 40) with 3.5 times mass of KOH at 650 C (NPGC650) exhibits the highest specific capacitance of 405 F g À1 at a current density of 0.2 A g À1 . Particularly, the specific capacitance still remains at 249 F g À1 even at a current density as high as 10 A g À1 . Moreover, 96% of the capacitance can be retained after 1000 cycles even under a high operation current of 10 A g À1 . The present work provides a novel strategy to synthesize NGPC electrode material for supercapacitors.

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