Fine Regulate the Process of Exfoliation of Graphite to Prepare Graphene

Abstract

The use of graphene (Gr) has led to great breakthroughs because of its excellent mechanical strength, high electric and thermal conductivity, catalytic properties, etc. Industrial applications of this material are hindered by the absence of high-volume production method of high-quality Gr. Electrochemical exfoliation of graphite is a promising method for mass production of Gr. The key issue is the difficulty of controlling the intercalation and tailing processes, which occur in almost the same potential region. Nevertheless, we realized that these processes are different kinetically and designed various programmed strategies of potential modulation for electrochemical exfoliation. High-quality Gr (≤ 5 layers) was obtained from highly oriented pyrolytic graphite (HOPG), with a yield of 96% and an average area greater than 230 μm2. The programmed electrolysis applies to commercial graphite rods with a yield of 58% (≤ 5 layers) and an average area about 50 μm2. The molecular ratio of carbon over oxygen (C/O) was confirmed as 22.7, indicating an oxidation degree as low as 4.4 %, and excellent electron transport and electron transfer properties. The specific capacitance of the prepared layer Gr by commercial graphite rods was 135 F g-1. The programmed electrolysis opens a promising route to the mass production of Gr, which is crucial for the follow-up modification and assembly of graphene for industrial applications.