The demand for high-capacity
energy storage along with high power
output and faster charging has made supercapacitors a key area of
energy research. The charge storage capacity of capacitors is largely
dependent on the electrode materials utilized. To that end, graphene
oxide (GO) and reduced GO (RGO) have been extensively employed for
preparing supercapacitors. However, to date, no study has reported
utilizing a GO/RGO bilayer electrode material for supercapacitor application.
Herein, we report the synthesis of GO/RGO bilayer electrodes on fluorine-doped
tin oxide (FTO) conducting substrates with four different combinations,
namely, RGO-RGO, RGO-GO, GO-RGO, and GO-GO. Electrochemical capacitance
analysis based on a symmetrical electrode configuration revealed that
FTO-GO-RGO electrodes had the best areal capacitance performance.
However, the highest specific areal capacitance (27.85 mF/cm2) for both symmetric/asymmetric configurations was achieved with
FTO-GO-RGO as the anode and FTO-GO-GO as the cathode. The heterogeneous
capacitance performance of the GO/RGO bilayer systems was analyzed
based on structural characterization and computational simulation
methods. Based on our analysis, we identified that inter-/intralayer
molecular interaction of the GO/RGO bilayer sheets through the confinement
pressure effect might have prompted their unique physicochemical properties.
This work highlights the importance of probing multilayer GO/RGO electrode
fabrication methods for preparation of high-capacity supercapacitors
through fine-tuning their structural and molecular properties.