Influence of synthesis route on the supercapacitor performance of graphene oxide-based composites

Abstract

The influence of synthesis route on the supercapacitor performance of graphene oxide (GO)- based composites was systematically investigated in a representative case involving cobalt ferrite nanoparticles. Particular emphasis was placed on understanding how surfactant presence and post-synthesis processing affect the electrochemical behavior of the resulting materials. Three nanoparticle synthesis strategies were explored: preparation with surfactant, preparation without surfactant, and synthesis with surfactant followed by its removal through thermal treatment prior to composite formation. The composites were then fabricated either through direct hydrothermal treatment or by mixing pre-formed nanoparticle and GO suspensions followed by thermal treatment in an inert atmosphere. In addition, the nanoparticle loading was varied between 15 wt% and 30 wt%, and a simultaneous hydrothermal synthesis of nanoparticles and composite from precursors was also evaluated. Galvanostatic charge– discharge measurements revealed a strong dependence of capacitance on both synthesis route and interfacial assembly conditions. The composite prepared via the hydrothermal route with 15 wt% nanoparticle content synthesized in the presence of surfactant exhibited the highest specific capacitance among all samples. This enhancement is attributed to improved nanoparticle dispersion, stronger coupling between GO sheets and active particles, and the preservation of oxygen functionalities beneficial for charge storage. These findings demonstrate that careful control of synthesis pathways—particularly the use of surfactant- assisted hydrothermal processing—plays a decisive role in optimizing the electrochemical performance of GO-based supercapacitor materials.