Anion Influence on Graphene Yield from Anodic Exfoliation of Coal-Derived Graphite: A Novel Precursor for Graphene Production

Abstract This study represents a significant advancement in graphene production through the electrochemical exfoliation of coal-derived graphite, focusing on anodic processes. Carbon foams, known for their lightweight structure and excellent electrical, mechanical, and thermal properties, were the starting material. The resulting graphene was analyzed for its morphology (scanning electron microscopy, field-emission scanning electron microcopy, transmission electron microscopy, atomic force microscopy), structural characteristics (Raman, X-ray diffraction), and chemical properties (Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy). The findings indicate that coal-derived graphite is a promising alternative for graphene production. The study also explores how different aqueous electrolytes affect the exfoliation process, focusing on the roles of anions as the active intercalants in anodic exfoliation. Specifically, Na2SO4 and KCl electrolytes were investigated. Exfoliation with KCl, involving chloride anions, produces graphene with fewer defects and a more ordered structure. In contrast, exfoliation with Na2SO4, driven by sulfate anions, results in graphene with more defects and oxygen-containing functional groups. These findings emphasize the critical role of the chemical environment in shaping the quality of exfoliated graphene, reinforcing coal-derived graphite as a promising graphene source.