Electrochemical impedance spectroscopy correlation among graphene oxide/carbon fibers (GO/CF) composites and GO structural parameters produced at different oxidation degrees
André F. Sardinha, Dalva Alves de Lima Almeida, N.G. Ferreira
Abstract
Graphene oxide (GO) with different oxidation degrees was systematically studied. This approach took into account GO synthesis with five oxidation degrees using 2.0, 2.5, 3.0, 4.0, and 5.0 g of oxidizing agent for each 1.0 g of graphite. The oxidation degree control provided surface functional group changes indicating the proper interaction between the carbon fiber (CF) surface and GO deposit. GO samples were structurally and physically evaluated by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction measurements. Mildly chemically oxidized CF was used to produce five different composites GO/CF analyzed by electrochemical impedance spectroscopy measurements (EIS). GO structural results showed well-corroborated data for the GO4.0 samples. EIS responses also aggregated important information associated with the composite charge transfer resistances as well as to their capacitive behaviors.