Synthesis of two-dimensional porous carbon nanosheets for high performance supercapacitors

Abstract

• Two-dimensional porous carbon nanosheets was prepared by a simple way. • The optimized electrode shows good electrochemical performance. • The symmetric supercapacitor delivers high energy density. Two-dimensional (2D) porous carbon nanosheets (PCNs) have drawn tremendous concern due to they possess large specific surface area, reduced ion transportation resistance and shorten ion diffusion distance. However, the traditional template method is complex and time-consuming. Here, we reported a convenient strategy to synthesize 2D PCNs derived from cationic starch using graphene oxide (GO) as template through an electrostatic self-assembly strategy with KOH activation. Due to the unique 2D highly interconnected nanosheet-like porous framework with suitable specific surface area, the as-prepared PCNs-1 electrode delivers high specific capacitance (232.1 F g −1 at 2 mV s −1 ) and impressive electrochemical stabilization (100.3% retention after 10,000 cycles) in 6 M KOH aqueous electrolyte. Meanwhile, the constructed PCNs-1//PCNs-1 symmetrical supercapacitor shows an energy density of 19.2 Wh kg −1 and remarkable electrochemical stabilization (93.7% retention after 10,000 cycles) in 1 M Na 2 SO 4 aqueous electrolyte. The strategy provides a novel and convenient approach to construct porous carbon nanosheets for supercapacitors.