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Umeå researchers has shown how activated graphene, activated carbon and other hydrophobic carbon species can be dissolved in water in the form of micrometer-sized particles.
The most common method to date for producing dispersions with graphene-related material is to use organic solvents and very strong mechanical treatment. However, organic solvents are often toxic, while mechanical treatment not only requires time and energy, but also introduces a number of defects that negatively affect the conductivity of the material.
Adding Graphene Oxide to Produce Stable Water Dispersions
Researchers from Umeå University have found a simple and environmentally friendly solution to the problem in the form of oxidized graphene, graphene oxide. Graphene oxide is hydrophilic and easy to dissolve in water.
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What we discovered is that stable water dispersions can be produced by adding a certain amount of graphene oxide to various hydrophobic carbon materials," says Alexandr Talyzin, associate professor at the Department of Physics at Umeå University.
Testing Method for High Surface Area Carbon
The research team tested the method for high surface area carbon such as graphene, activated graphene, porous or activated carbon. The dispersions were stable even after a number of days. When the added carbon nanotubes in the dispersion proved to be good for producing electrodes for super capacitors. The dispersion was applied to metal foil, dried and heated to 200° C. All these steps could easily be scaled up to industrial production, the researchers say.
The dispersions can also be useful for many applications, such as inks for printing, protective coatings and conductive colors.
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What we get in the end is a thin film of conductive electrode material with high surface area, good conductivity and excellent performance when storing electricity in super capacitors. The high surface area is provided by the micrometer particles of, for example, activated graphene, while nanotubes and thermally reduced graphene oxide provide good electrical contact between the particles", says Alexandr Talyzin.
The research is funded by the EU Graphene Flagship, a huge international project aimed at bringing the graph to the market. Researchers have also received much support from Umeå University. The method of preparing activated graphene dispersions also appeared to be worthy of patenting.
Source: Umeå University