Intrinsic Properties of GO/RGO Bilayer Electrodes Dictate Their Inter-/Intralayer Intractability to Modulate Their Capacitance Performance

Abstract

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.

Recent Progress Using Graphene Oxide and Its Composites for Supercapacitor Applications: A Review

“…(c) HOMO-LUMO molecular orbitals for the optimized structures of various electrodes using DFT. (d) HOMO-LUMO molecular orbitals for the optimized structures of various electrodes with K + and Cl − ions using the COSMO solvation system (reproduced from [136]). Copyright 2023, The American Chemical Society.…”

“…The simulation studies determined that N-doped graphene (CQ = 0) and epoxide-hydroxyl-treated graphene (CQ = 34.6 µF cm −2 ) could potentially serve as positive and negative electrodes, respectively, in an asymmetric supercapacitor, based on their respective CQ values. Islam et al recently employed DFT simulation to examine the electronic structure of single-layer (GO/rGO) and double-layer (rGO-GO, rGO-rGO, GO-GO, and GO-rGO) screen-printed electrodes by analyzing their highest occupied molecular orbital (HOMO) and highest occupied molecular orbital (LUMO) energy gaps [136]. The energy gap of HOMO and LUMO was discovered to be greater in a double-layer screen-primed electrode than in a single layer, as shown in Figure 10c.…”

Recent advances in energy storage with graphene oxide for supercapacitor technology

“…The result is a SC that can respond rapidly to demands for energy, making it an ideal choice for applications where quick power delivery is critical. 64,176–180 Another significant effect of GO on SCs is enhanced stability and durability. The robust nature of GO prevents electrode degradation over extended charge and discharge cycles.…”