A facile, safe and controllable morphology synthesis of rGO_Cu2O nanocomposite as a binder-free electrode for electrochemical capacitors

This paper reports the exploitation of Cu2O nanoparticles and reduced graphene oxide (rGO) in a sonication treatment for the production of rGO- Cu2O imperfect micro-cubes nanocomposite. This strategy was implemented in order to fabricate a hybrid binder-free electrode for electrochemical energy storage into supercapacitors. Instead of hazardous chemical compounds, Ascorbic acid was simultaneously used as reducing agent and morphology controller of the nanocomposite as well. The structural properties of rGO-Cu2O imperfect micro-cubes nanocomposite were studied by X-Ray diffraction (XRD) analyses, field emission scanning electron and transmission electron microscopy (FE-SEM and TEM) imaging, energy dispersive X-ray (EDX) elemental mapping, X-ray photoelectron spectroscopy (XPS) and surface area analyses. Based on structural investigation, the rGO-Cu2O nanocomposite with the morphology of attached Cu2O imperfect micro-cubes to rGO nanosheets possessing a high surface area containing pores and channels in different sizes was used as electrode materials for the charge storage. Electrochemical measurements including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS) and XPS analysis revealed that rGO-Cu2O imperfect micro-cubes nanocomposite modified electrode without binder has used three distinct processes of forming electrochemical double layer, redox reactions and ion diffusion for charge storage somehow it is introduced as a hybrid binder-free electrode. According to the GCD analysis, the stored charge value was calculated 960 C.g−1 at current density of 1 A.g−1, the cycling stability was examined in that the 87% of initial stored charge value was remained after 10,000 cycles.