SELF-ASSEMBLY OF CHEMICALLY CONVERTED GRAPHENE FOR SUPERCAPACITORS

摘要

Graphene oxide (GO) has attracted a great deal of attention in recent years, mainly due to that it is a unique precursor of chemically converted graphene (CCG). GO is usually synthesized by exfoliation of graphite oxide (multilayered GO) prepared by the oxidation of natural graphite powder in acidic media. The typical method of synthesizing graphite oxide was developed by Hummers and co-workers. A GO sheet obtained from the graphite oxide synthesized by Hummers' method usually has a lateral dimension in the range of submicrometer to several tens of micrometers and its thickness was measured to be around 1 nm. This thickness value is much higher than a clean graphene sheet (around 0.3 nm) because of the presence of various oxygenated groups (e.g. hydroxyl, epoxide and carboxyl). The hydroxyl and epoxide groups of GO are mainly on its basal plane and carboxyl groups are predominately at its edges. As a result, the basal plane of a GO sheet is more hydrophobic than its edge. It behaves like a two-dimensional amphiphilic macromolecule. The atom-thick two-dimensional (2D) structure of GO sheets provides them with various new supramolecular behaviors comparing with conventional low-dimensional counterparts such as carbon dots and carbon nanotubes.