ABSTRACT
Graphene being a two-dimensional material has recently been attracting huge research attention; this can be credited to its outstanding intrinsic behaviours (ranging from enormous surface area, thin as well as flexible structure, thick and transparent, high thermal and electrical conductivity), which have afforded it wide-ranging applications in various fields, and mostly for energy storage research. This chapter presents the properties, synthesis routes, and the electrochemical performance of graphene. Carbon can exist in varying structural configurations such as zero-dimensional structure observed in fullerenes, one-dimension as observed in carbon nanotubes, two-dimensional structure as seen in graphene, and the three-dimensional structure of graphite. The two-dimensional graphene thin sheet is a building block for all the graphitic/carbon nanostructures; it becomes fullerene when cut and bent into a spherical structure thus exhibiting a zero-dimensional shape; rolling up a graphene sheet turns it into the one-dimensional structure known as carbon nanotube (CNT). Detailed synthesis steps for obtaining quality and large-scale graphene oxide using the Hummers method were reported. This method involves a chemical exfoliation of graphite, while a thermal degradation of graphene oxide precisely at 350˚C results in reduced graphene oxide. Reports on various electrochemical behaviours of graphene-based electrodes utilized in supercapacitors and batteries were also outlined. The excellent electrochemical performance associated with graphene-based energy storage electrodes is ascribed to such fascinating properties as great surface area, outstanding electron mobility, chemical and thermal stability, thin and flexible structure, coupled with its oxygen-rich functional groups and wide range of operating potential. An insight into the specific new features/innovations brought by graphene into the energy storage systems is provided.
