Green synthesis of nitrogen-doped hierarchical porous carbon nanosheets derived from polyvinyl chloride towards high-performance supercapacitor

Green and cost-efficient preparation of two-dimensional (2D) hierarchically porous carbon nanosheets for supercapacitors draw extensive attention due to their unique microstructure and excellent electrochemical performance. In the present work, polyvinyl chloride-derived nitrogen-doped hierarchically porous carbon nanosheet materials were successfully synthesized through a one-pot carbonization process, which contained in-situ generated CaCO3 template and K2CO3 activation agent coupled with the N-doping and blowing effect of melamine. The optimal carbon sample with nitrogen-doping presented unique 2D morphology, high specific surface area (2546.6 m2 g−1), and micropore-dominant hierarchical pores. Benefiting from these merits, it delivered a high specific capacitance of 347.0 F g−1 at 0.5 A g−1 in 6 M KOH electrolyte in a three-electrode system. Furthermore, the assembled symmetric supercapacitor demonstrated an excellent energy density of 25.7 Wh kg−1 at a power density of 90.0 W kg−1 in 1 M Na2SO4 electrolyte and superior cycling stability of 98.2% retention of initial capacitance after 5,000 cycles. Eventually, it is expected to provide an environmentally friendly and feasible method to obtain porous carbon electrode materials with 2D nanosheet structure for high-performance energy storage applications. [Display omitted] •2D porous carbon nanosheet materials are synthesized by one-pot pyrolysis.•In-situ generated CaCO3 and K2CO3 act as template and activation agent, respectively.•Blowing effect of melamine promotes the formation of 2D structures.•The material displays a high capacitance 347.0 F g−1 and excellent rate capability.•The symmetric supercapacitor shows a high energy density of 25.7 Wh kg−1.