Highly efficient electrolytic exfoliation of graphite into graphene sheets based on Li ions intercalation–expansion–microexplosion mechanism

In this communication, we report a facile and novel molten salt electrolysis method to prepare high-quality graphene sheets. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) confirmed that the final products exfoliated from the electrolysis of graphite cathode in the molten LiOH medium are mainly graphene sheets (approx. 80 wt% conversion efficiency). Raman spectroscopy revealed that the as-formed graphene sheets have significantly low density of defects. Based on these observations, the exfoliation mechanism of graphite cathode into graphene sheets through lithium intercalation–expansion–microexplosion processes was proposed. The discovery of a molten salt electrolysis method presents us with the possibility for large scale and continuous production of graphene.