Supercapacitor study of reduced graphene oxide/Zn nanoparticle/polycarbazole electrode active materials and equivalent circuit models

In this study, graphene oxide (GO) was chemically reacted with sodium borohydride (NaBH4) to form reduced graphene oxide (rGO). rGO and rGO/Zn nanoparticle/polycarbazole (rGO/Zn/PCz) nanocomposite were synthesized by in situ chemical reactions. Nanocomposites were examined by scanning electron microscopy-energy-dispersive X-ray analysis (SEM-EDX) and Fourier-transform infrared spectroscopy-attenuated transmission reflectance (FTIR-ATR). Supercapacitor device performances were taken as two-electrode configuration. Electrochemical measurements of supercapacitors were tested by galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). rGO/Zn/PCz nanocomposite shows increased capacitance (C-sp=33.88F/g) compared to that of rGO (C-sp=20.78F/g), PCz (12.57F/g), and Zn/PCz (19.05F/g) at the scan rate of 10mV/s by CV method. Ragone plots were drawn to observe performances of supercapacitor devices. The enhanced capacitance results in high-power (P=442.5Wkg(-1)) and energy-storage (E=1.66Whkg(-1)) capabilities of the rGO/Zn/PCz nanocomposite material. Stability tests were examined for 1000cycles by CV method.