EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Graphene is a promising material for different applications due to its high surface area, conduc-tivity and possibility of chemical modification; but technical material production of greater quantities is yet difficult and expensive. Electrochemical exfoliation processes appear to be a viable solution to produce single-sheet to few-layered graphene oxide powder from graphite. Based on this assumption a three-step exfoliation process was developed to produce graphene oxide in higher quantities.
The exfoliation process was executed within a cooled double-wall reactor with mechanical stir-ring. As working electrode and counter electrode graphite rods were used to prevent contamina-tion. After a pretreatment step, the electrochemical exfoliation was executed consuming the working electrode. After ultrasonication for exfoliation promotion, filtration, washing and drying of the powder, fine grained graphene oxide flakes were gained.
The product powder was afterwards characterized by Raman-, IR-spectroscopy, SEM-EDX, Thermogravimetric measurements, X-ray powder diffraction and powder conductivity meas-urements. Raman-spectrocopy showed a significant increase of the D-band and a shift of the G-band compared to the educt material. SEM-EDX measurements showed small flakes with few µm length. Thermogravimetric measurements showed mass losses of about 20 w% above 100 °C corresponding to the loss of oxidic groups. XRD confirmed the assumption of few-layered graphene structure with oxidic residues.
With the combination of good conductivity and the possibility of chemical modification, the produced powder is applicable for various different applications like integration into compo-sites. Due to the up-scaling potential, industrial production via this route is possible. Further in-vestigations regarding the reduction and chemical modification, as well as the implementation in composite material will show application possibilities in the areas of de-icing and flame-inhibition within polymer composites, interesting for the aeronautical industry.