Graphene (Graphene) is composed of carbon atoms in single chip structure with sp2 hybrid orbital type hexagonal honeycomb lattice of thin film. It is a 2D material and for a long time, it was considered as a hypothetical structure.
In 2004, Andre Geim and Konstantin Novoselov, scientists in the University of Manchester successfully isolated graphene from graphite. The result confirmed that graphene can exist alone. Therefore, Andre Geim and Konstantin Novoselov won the Nobel prize in Physics in 2010 for groundbreaking experiments regarding the two-dimensional material graphene.
Graphene’s stable structure: carbon atoms of graphene are connected by covalent bond, which has higher stability than chemical bond. Between electrons in graphene are honeycombed grid, creating strong interaction similar to the surface of graphite.
Ultra thin characteristics: Graphene is a kind of carbon materials that is from monolayer of carbon atoms in the surface material. The thickness of graphite crystal film is only 0.335nm (the diameter of an atom). Adding 200000 pieces of film together, the thickness is similar to a single hair.
Ultra high electrical conductivity: Graphene is one of the best materials in electrical conductivity. The movement of carrier (electronic) reached 1/300 of the speed of light, far more than the electronic velocity in general conductor (high electron mobility).
Excellent flexibility: So far, the researchers have not found graphene in absence of carbon atoms. The connection of carbon atoms in graphene is so flexible. When applying the external mechanical force, the surface of carbon atoms is bending deformation, so that the carbon atoms do not have to rearrange to adapt to the external force and keep stable structure.
Excellent anti-interference feature: When electrons in graphene are moving in orbit, the inter-atomic force is strong. In normal temperature, even if the surrounding carbon atoms bumped against, the interference of electronic in graphene is very small.
High surface hardness: Like diamonds, graphene has the highest intensity substance, with the strength more than 100 times of steel.
The application of graphene:
Chinese academy of sciences predicted graphene material could be widely used in integrated circuit devices. More application fields include micro-nano electronics, photoelectrochemical cell, ultralight aircraft materials. Colin Bailey, Vice-President and Dean of the Faculty of Engineering in the University of Manchester, said that graphene could completely change the large number of applications, “from smartphone and super-fast broadband to drug transport and computer chips.”
Paint: Graphene can improve the coating ratio when applying to electrostatic spraying, and thus reduces the paint cost and VOC evaporation; besides, the graphene-based paint can generate a light-colored primer. For anti-corrosive coating, graphene flakes form dense layers of isolation in the matrices, and thus prevent the diffusion of ions and reduce the corrosion.
Leather coating: graphene largely enhances the abrasion resistance of leathers, and improves the antistatic behaviors, flame retardance, and UV protection.
Polymer composites: A single-layered graphene was demonstrated to possess a Young’s Modulus up to 1 TPa and tensile strength of 130 GPa. When graphene is applied to polymer composites as fillers, it can significantly enhance the mechanical strength in various perspectives and the abrasion resistance of the matrices. In some other cases, graphene is employed to alter polymers’ thermal or electrical conductivity.
Alloys: Graphene can be integrated into metals and displays excellent compatibility, showing no obvious interfaces or phase separation. Moreover, the mechanical properties and processing efficiency of these alloys can be largely improved.
Biological or medical applications: Graphene has an extremely large surface area, and can accommodate a much larger number of active molecules than other nanomaterials. As a result, graphene (or graphene oxide) may serve as carriers for functional ingredients in various field, in order to improve the water solubility or stability of these hydrophobic molecules.
Li-ion batteries: graphene oxide (GMO), a brand new semiconductor material, would enhance the efficiency of Li-ion anodes. Employing graphene electrode as the cathode will shorten the charging intervals of Li-ion batteries from 2 hours to 10 minutes.
Supercapacitors: a supercapacitor is a new-type, highly efficient energy-storage device, which can be charged through charge accumulation on the electrode surfaces. They have large energy density and much greater power density than rechargeable batteries, and they can accept and deliver charge very fast, tolerate many charge and discharge cycles, and work at a wide range of voltage and temperature.
Touch screen of mobile phones: the manufacture of graphene touch screen is environment-friendly and requires few resources. Moreover, the cost will become much less than traditional Indium Oxide touch screen with the improvement of manufacturing techniques.
Desalination of sea water: graphene material is modified accordingly to attract or repel water molecules, through precise control over the pore sizes of porous graphene, integration of other additives, and thus the alteration of the hydrophilic properties of graphene edges.
Cooling film: Graphene possesses excellent thermal conductive properties, with a thermal conductivity coefficient as high as 5300 W/m•K for a single-layered graphene. Therefore, graphene-based film can be applied to cooling of various electronic instruments.