Exfoliation Mechanism of Graphite Cathode in Ionic Liquids

Haiping Lei; Jiguo Tu; Zhijing Yu; Shuqiang Jiao

doi:10.1021/acsami.7b03306

Exfoliation Mechanism of Graphite Cathode in Ionic Liquids

ACS Appl Mater Interfaces. 2017 Oct 25;9(42):36702-36707. doi: 10.1021/acsami.7b03306. Epub 2017 Oct 11.

Authors

Haiping Lei¹, Jiguo Tu¹, Zhijing Yu¹, Shuqiang Jiao¹

Affiliation

¹ State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing , Beijing 100083, PR China.

PMID: 28972779
DOI: 10.1021/acsami.7b03306

Abstract

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.

Keywords: Al-ion battery; electrochemical exfoliation; graphene; intercalation; ionic liquid.