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Figure 5: (a) Schematic illustration for fabricating crumpled nitrogen-doped graphene; TEM images of (b) GO, (c) GO-C3N4, and (d) C-NGNSs; (e) CVs of C-NGNSs-900 supercapacitors in 1.0 M [Bu4N]BF4 acetonitrile solution between −1.5 and 1.5 V at different scan rates; (f) specific capacitance dependence on potential sweep rates in different graphene-based supercapacitors with 1.0 M [Bu4N]BF4 acetonitrile solution as electrolyte [28].