The surface properties of the electrode materials play a crucial role in determining the performance and efficiency of energy storage devices. Graphene oxide and nanostructures of 3d transition metal oxides were synthesized for construction of electrodes in supercapacitors, and the electronic structure and oxidation states were probed using near-edge X-ray absorption fine structure. Understanding the chemistry of graphene oxide would provide valuable insight into its reactivity and properties as the graphene oxide transformation to reduced-graphene oxide is a key step in the synthesis of the electrode materials. Polarized behavior of the synchrotron X-rays and the angular dependency of the near-edge X-ray absorption fine structures (NEXAFS) have been utilized to study the orientation of the σ and π bonds of the graphene oxide and graphene oxide–metal oxide nanocomposites. The core-level transitions of individual metal oxides and that of the graphene oxide nanocomposite showed that the interaction of graphene oxide with the metal oxide nanostructures has not altered the electronic structure of either of them. As the restoration of the π network is important for good electrical conductivity, the C K edge NEXAFS spectra of reduced graphene oxide nanocomposites confirms the same through increased intensity of the sp2-derived unoccupied states π* band. A pronounced angular dependency of the reduced sample and the formation of excitonic peaks confirmed the formation of extended conjugated network.

Great focus has been directed towards double-layer capacitance and Faradic, redox reactions because of their long device lifetimes and their high power densities, respectively. Our novel approach to combining these mechanisms in a tri-layered composite electrode promises to increase the energy densities of the device, without sacrificing the supercapacitance and the high power densities attributed with it. Initial analysis of the interfacial interactions of graphene oxide (GO) and manganese oxide (MnO2) were promising. This paper aims to further demonstrate the tri-layered composite by forming a layer of reduced graphene oxide (rGO) on MnO2 nanowires and cobalt oxide nanorods. We have successfully created the first of a kind supercapacitor electrode material as a scalable device. In this paper, in addition to analysis of the composite electrode, we present modifications to the traditional electrophoretic deposition process and optimizations to the thermal reduction of GO in order to create rGO surfaces on substrates that are normally difficult to adhere it to.