Tuning the Supercapacitive Properties in Graphene Oxide/Cobalt Ferrite Nanocomposites by Synthesis Routes

Abstract

Graphene oxide (GO), a two-dimensional carbon-based material rich in oxygen-containing functional groups, has attracted significant attention for supercapacitor applications in recent years. The abundance of carboxyl, hydroxyl, and epoxy groups on its surface not only improves its dispersibility in aqueous media but also provides active sites for interaction with metal oxides, making GO an ideal matrix for nanocomposite development aimed at enhancing electrochemical performance. Among the various metal oxides, cobalt ferrite (CoFe2O4, CFO) nanoparticles have emerged as promising candidates for pseudocapacitive applications owing to their intrinsic redox activity and structural stability. However, their relatively low conductivity limits their standalone performance, necessitating integration with conductive matrices like reduced GO. This work focuses on the synthesis and optimization of GO/CFO nanocomposites for improved supercapacitor performance by systematically tailoring synthesis parameters. Two CFO loading ratios (15 wt% and 30 wt%), two post-synthesis modification routes (thermal and hydrothermal treatment), two mixing strategies (mechanical stirring and ultrasonic dispersion) and presence of surfactant on CFO, were investigated to assess their impact on the electrochemical performance of the resulting materials. Galvanostatic charge/discharge (GCD) measurements were employed to evaluate specific capacitance. The results clearly demonstrate that the composite prepared using the hydrothermal route, with 15 wt% CFO content and ultrasonic dispersion, exhibited the highest capacitance among all samples. This improvement is attributed to enhanced particle dispersion, better interfacial contact between GO sheets and CFO nanoparticles, and the preservation of functional groups conducive to charge storage. These findings highlight the importance of synthesis strategy in optimizing the electrochemical properties of GO-based nanocomposites and pave the way for the development of next-generation energy storage materials.