Raman spectroscopy was used to analyze

Electrochemical measurements
The supercapacitor electrodes were prepared by pasting the mixture of the obtained G/NiO composite, acetylene black and polytetrafluoroethylene (PTFE) with FTI 277 HCl weight ratio of 8:1:1 onto nickel foam. A 2 M NaOH aqueous solution was used as the electrolyte. The electrochemical properties of the packaged button-type supercapacitor were analyzed by cyclic voltammetry (CV), galvanostatic charge/discharge measurements (GCD) and electrochemical impedance spectroscopy (EIS).