Exfoliation Mechanism of Graphite Cathode in Ionic Liquids.

Graphene has been successfully electrochemically exfoliated by electrolysis of cathode graphite in the aluminum-ion battery with ionic liquid electrolyte comprising AlCl3 and 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl). The AlCl4-, Al2Cl7-, etc., intercalation into graphite flakes in ionic liquid of the aluminum-ion battery by different electrolysis processes to exfoliate graphite has been researched in detail. As a result of the enhanced structural flexibility, the intercalant gallery height increases in the less than five-layer graphene film, providing more free space for AlCl4-, Al2Cl7-, etc. transport. Therefore, a quantity of 3-5 layers rather than 1-2 layers of graphene can be obtained. The results clearly demonstrate that graphene has been produced in the graphite cathode in AlCl3/EMImCl ionic liquids, which is significantly meaningful for accelerating the theoretical research and industrialized application of graphene. Meanwhile, it has a vitally important role for promoting the recycling Al-ion batteries.