Nitrogen implanted carbon nanosheets derived from Acorus calamus as an efficient electrode for the supercapacitor application

•The nitrogen implanted carbon synthesized from Acorus Calamus for the first time.•The XPS analysis showed 2.9% of nitrogen atom is implanted in the activated carbon.•The Raman spectra showed the exfoliated activated carbon ID/IG ratio of 1.04.•The activated carbon (C-750) exhibited the enhanced specific capacitance of 353.3 Fg−1 at 1 Ag−1.•The energy and power densities of C-750 obtained to be 47.2 and 16,000 Wkg−1, respectively.