Bipolar anodic electrochemical exfoliation of graphite powders

• Published in: Electrochemistry communications Vol. 104; p. 106475
• Main Authors: Hashimoto, Hideki, Muramatsu, Yusuke, Nishina, Yuta, Asoh, Hidetaka
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2019; Elsevier
• Subjects: Anode; Bipolar electrochemistry; Electrochemical exfoliation; Graphene; Graphene oxide; Graphite; Graphene oxide; Anode; Graphene; Bipolar electrochemistry; Graphite; Electrochemical exfoliation
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2019.06.001

The electrochemical exfoliation of graphite has attracted considerable attention as a method for large-scale, rapid production of graphene and graphene oxide (GO). As exfoliation typically requires direct electrical contact, and is limited by the shape and/or size of the starting graphite, treatment of small graphite particles and powders, the typical form available commercially, is extremely difficult. In this study, GO nanosheets were successfully prepared from small graphite particles and powders by a bipolar electrochemical process. Graphite samples were placed between two platinum feeder electrodes, and a constant current was applied between the feeder electrodes using dilute sulfuric acid as the electrolyte. Optical microscopy, atomic force microscopy, X-ray diffractometry, Raman spectroscopy, and X-ray photoelectron spectroscopy were employed to examine the samples obtained after electrolysis. The results obtained from these analyses confirmed that anodic electrochemical exfoliation occurs in the graphite samples, and the exfoliated samples are basically highly crystalline GO nanosheets with a low degree of oxidation (C/O = 3.6–5.3). This simple electrochemical method is extremely useful for preparing large amounts of graphene and GO from small particles of graphite. [Display omitted] •A bipolar anodic electrochemical exfoliation process for graphite was developed.•Graphite powder with particle sizes of 20–500 μm can be exfoliated.•The exfoliated products are graphene oxide nanosheets.