Fig. 2From: Supercapacitors with alternating current line-filtering performanceReproduced with permission from Ref [9]. Copyright 2012. Macmillan Publishers Limiteda Scanning electron microscope (SEM) micrograph vertical aligned graphene on the Ni surface; b impedance phase angle versus the frequency for a graphene nanosheet-based capacitor, commercial aluminum electrolytic capacitor, and activated carbon-based capacitor; c capacitance versus the frequency of the graphene nanosheet capacitor; Reproduced with permission from Ref [12]. Copyright 2019. AAAS. d cross-sectional SEM image of the ErGO electrode; e plot of the impedance phase angle versus the frequency; and f plot of specific capacitance versus the frequency.Back to article page