Regulation of radicals from electrochemical exfoliation of a double-graphite electrode to fabricate high-quality graphene

Abstract

Manipulation of conditions during the electrochemical exfoliation of graphite is in great demand for the large-scale manufacture of high-quality graphene. Here, we developed a new electrolysis system to manufacture high-quality graphene using double-graphite foil as an electrode. We employed alternating currents to the power system. Graphene with sulfur particles on the surface (GSP) was successfully prepared by adding thiourea into the ammonium sulfate electrolyte. CH₄N₂S acted as a source of sulfur and regulated the radicals (e.g., HO˙). Thus, exfoliation was controlled. The as-prepared GSP (1% CH₄N₂S) displayed a relatively high electromagnetic interference (EMI) shielding effectiveness (SE) value of 32.46 dB (thickness of 0.208 mm). In the meantime, we study and confirm that the free radicals could also be regulated by lowering the temperature. The as-prepared graphene exhibited an EMI SE value of 21.05 dB (thickness of 0.239 mm), when the temperature of the electrochemical exfoliation was reduced to 20 °C.