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

Abstract

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.