One-step synthesis of annual ring-shaped planar nitrogen/sulfur co-doped nanoporous graphene for supercapacitance

Heteroatom-doped nanoporous graphene has great potential as emerging energy storage materials, but the complex synthetic routes and disordered structure limit the improvement of supercapacitance performance. Herein, we develop a one-step synthesis strategy to obtain nitrogen/sulfur doped nanoporous graphene (NS-NG). Graphene oxides absorbed with dyes are burned in a confined interlayer of porous hydrotalcite for preparing NS-NG. Interestingly, the NS-NG retains the morphology of multilayer graphene oxides coated with fiber rods before combustion, so it exhibits the annual ring -shaped structure, larger surface area, and highly porosity. Importantly, the NS-NG not only shows a high specific capacitance of 325 F g −1 , and also has a high energy density of 25 Wh kg −1 at a high power density of 1906 W kg −1 with an excellent capacity retention of 86% after 10,000 cycles applied in the two-electrode symmetric supercapacitor at a current density of 2 A g −1 in 0.5 M Na 2 SO 4 aqueous solution.