Graphene-based composite materials

Abstract

Graphene, a single-layer carbon sheet with hexagonal lattice structure, has shown several unique characteristics such as the quantum Hall effect, high carrier mobility, large theoretical specific surface area, good optical transparency, high Young's modulus, and excellent thermal conductivity. A single square-meter sheet of graphene of weight 0.0077 g can support up to 4 kg. The two-dimensional structure, large surface area, and extraordinary mechanical characteristics make graphene a potential candidate as a nanofiller in a variety of composite materials. The significant advantages are as follows: the possibility to enhance the mechanical properties even with a relatively low nanofiller (graphene), effective dispersion, interface chemistry, and nanoscale morphology. The exceptional properties and the variety of additional incredible traits make graphene one of the important materials in the future. It is predicted that graphene will revolutionize every industry known to man. To exploit these characteristics of graphene, different reliable synthetic techniques have been developed to fabricate graphene and its derivatives, ranging from the bottom-up epitaxial growth to the top-down exfoliation of graphite through oxidation, intercalation, and/or sonication. The increase in production of graphene and its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), offers numerous possibilities to fabricate graphene-based functional materials for a variety of technological applications. The incredible improvement has been achieved with graphene-based composites, where the performance depends on the inherent characteristics of the nanofiller (as graphene and its derivatives). The addition of graphene and its derivatives to the host matrix allows the improvements in the composite characteristics to be used in a variety of applications such as electric, optics, electrochemical energy conversion, storage, etc. The graphene as nanofiller has been successfully added to inorganic nanostructures, organic crystals, polymers, biomaterials, metal-organic frameworks, etc. The modifications allow interactions or chemical bond formation between the nanocrystals (host material) and/or graphene sheets. Significant enhancements in the electrical conductivity, thermal stability, and mechanical characteristics are achieved by the addition of graphene and its derivatives to nanocomposites, which are explored for applications such as batteries, supercapacitors, fuel cells, photovoltaic devices, photo-catalysis, sensing platforms, and so on.