AUTHOR=Park Si-Woo , Jang Byungkwon , Kim Han , Lee Jimin , Park Ji Young , Kang Sung-Oong , Choa Yong-Ho 

TITLE=Highly Water-Dispersible Graphene Nanosheets From Electrochemical Exfoliation of Graphite

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 9 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.699231

DOI=10.3389/fchem.2021.699231

ISSN=2296-2646

ABSTRACT=The electrochemical exfoliation of graphite has been considered to be an effective approach for the mass-production of high-quality graphene due to its easy, simple, and eco-friendly synthetic features. However, water-dispersion of graphene produced in the electrochemical exfoliation method also has been a challenging issue because of the hydrophobic properties of resulting graphene. In this study, we report the electrochemical exfoliation method of water-dispersible graphene importantly containing the relatively low oxygen-content <10 % without any assistant dispersing agents. Through the mild in-situ sulfate-functionalization of graphite under control of alkaline electrochemical conditions using a pH buffer, the highly water-dispersible graphene could be produced without any additional separation processes of sedimentation and/or centrifugation. We found the resulting graphene sheets to be with the high crystalline basal planes, lateral sizes of several μm, and thickness <5 nm. Furthermore, the high aqueous dispersion stability of as-prepared graphene could be demonstrated using a multi-light scattering technique, showing very little change in the optical transmittance and the terbiscan stability index over time.