Surface assembly of Fe3O4 nanodiscs embedded in reduced graphene oxide as a high-performance negative electrode for supercapacitors

In this work, iron oxide (Fe3O4) nanodiscs and anchored on reduced graphene oxide (rGO) as a nanocomposite (Fe3O4/rGO) have been fabricated through a surface, scalable hydrothermal process. The morphological and structural studies of Fe3O4/rGO nanodiscs are analyzed by various techniques such as XRD, XPS, SEM, TEM, and TGA, etc. The Fe3O4/rGO electrode is tested as a negative electrode in a basic potassium hydroxide (KOH) electrolyte using a three-electrode system for supercapacitor applications. The optimized electrochemical properties of Fe3O4/rGO are systematically compared with bare Fe3O4 and it is found that the rGO greatly enhanced its performance as a negative electrode. The Fe3O4/rGO nanodiscs demonstrated a notably high-specific capacitance of 1149 F/g at 1.5 A/g better than that of Fe3O4 nanodiscs (920 F/g at 1.5 A/g). Furthermore, the Fe3O4/rGO displays the superior cyclic stability of 97.53% after running continuous 10000 GCD cycles at a high current density of 10 A/g, while bare Fe3O4 attained 87.82% at identical conditions. The fascinating electrochemical performance can be benefited for future fabrications of iron graphene-based negative electrode material for SCs.