graphene oxide dispersion
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1. The core technology
The core technology of this project is to use oxidation-reduction method. The basic principle is using graphite as raw materials. With strong acid treatment, graphite is converted into graphite intercalation compounds in the solution. And then add strong oxidizing agent to oxide the graphite intercalation compounds that destroys the crystal structure of graphite. Graphite oxide or graphene oxide we get disperses in solution due to the oxygen-containing functional groups are introduced on the surface of graphite. Finally use various reduction methods to reduce graphene oxide, and get graphene with different sizes and thicknesses.
The core technology of this project is to reduce the graphene oxide. We use electrochemical reduction method to prepare graphene. It is a green and fast preparation method that can completely remove all kinds of oxygen-containing functional oxide in the oxide and reduce graphene oxide to graphene.
2. The innovative points
1) As raw materials, graphite is low-price and easy to get. It is simple for the preparation process of this method. Graphene we prepared by this method can disperse well in solution. The solution-processed graphene can be applied to any substrate via spin-coating. And then they can be applied to a large scale organic device, photovoltaic device and electrochemical device.
2) We have made some improvements and breakthroughs in the basic Hummers method so that graphene can be produced in large quantities. The production can reach an annual output of one ton or even a hundred tons.
3) During the production process of graphene, we can control the its sheet size. According to the different sheet sizes of graphene, we can divide them into a variety of specifications ranging from 50 to 5000mesh.
二、 Research significance
Since graphene was discovered in 2004, it has been known as the king of new materials. Graphene is the thinnest and hardest nanomaterial in the world. It is almost completely transparent, and its optical absorption is only 2.3%. Its thermal conductivity is as high as 5300W/（m•K） which is higher than carbon nanotubes and diamond. Its room-temperature electron mobility is above 15000cm²/（V•s） higher than carbon nanotubes and crystalline silicon. The electrical resistivity of graphene is the lowest which is 10^-6Ω•cm that is lower than cooper and silver.
The performance of graphene materials is so excellent that they are expected to change the world. But these magical materials are facing a serious problem that the output of graphene is painfully low. The high price of graphene leads to a rough patch ahead for the graphene industry. To solve this problem, the technical team of Carbon Century finally found out a preparation method which was successfully in mass production for graphene after many years of research. The single rate of graphene prepared by this method is more than 99%. It solves the problems of mass production an makes great contribution to the application of graphene.
三、 Achievement and advantage
1. The macroscopic preparation of graphene has been matured and turned to industrial production. At present, Carbon Century builds macroscopic production base of graphene respectively in ChangZhou, WeiFang, and other places.
2. The small-scale production pilot line we built had reached more than 5 kilograms per month (Single shift operation runs for 8 hours). The monolayer rate is above 99%.
3. The production line in WuXi put into operation in June of 2015. And the annual output of graphene reached 0.5 ton.
4. Controlling the production process and the changes of parameters, we can produce different specifications of graphene and graphene oxide. The products are as follows:
50 mesh, dry graphene powder
300 mesh, dry graphene powder
5000 mesh, dry graphene powder
50 mesh, solution-processed graphene
300 mesh, solution-processed graphene
5000 mesh, solution-processed graphene
50 mesh, dry graphene oxide powder
300 mesh, dry graphene oxide powder
5000 mesh, dry graphene oxide powder
50 mesh, solution-processed oxide graphene
300 mesh, solution-processed oxide graphene
5000 mesh, solution-processed oxide graphene
Graphene is a quasi-2D material with a thickness of a single carbon atom, and the thin planar film is composed of SP2 hybrid orbital of carbon atoms forming a hexagonal honeycomb lattice. It is one of carbon allotropes. Compared with other new materials, graphene has kinds of excellent properties. Due to its excellent physical property, graphene can be applied to slim and lightweight aircraft materials , super-tough body armor materials, space cable materials, etc. Owing to its fast transmission of electrons, graphene can be used as semiconductor materials, solar cell electrode materials, nanosensor materials, energy storage materials, etc. The electric conductivity of graphene is outstanding, and it can be applied in high frequency circuit and super computer chip.
Graphene can be used as LCD display materials, phohoelectric chemical battery materials, etc. because of its exceptional optical property. Graphene can be used as antibacterial materials because of its good biological performance. Graphene is also used in gas sensors and other fields.