The exceptional properties of Graphene include its ultra high tensile strength (100 times stronger than steel), excellent electrical and thermal conductivity and the thinnest 2D material known.
Graphene is then suitable for a wide range of next-generation applications including when utilized in 'layers' with other 2D nanomaterials. It is also the fundamental structural element of Carbon Nanotubes.
High Pressure Homogenization (HPH) is gaining in popularity as an effective mechanical Graphene exfoliation method. Learn more below.
Graphene exfoliation methods
Generally, two different strategies can be applied:
1. Top Down: Graphene produced from graphite by exfoliation - using any of the following methods - mechanical (including our Homogenizers), chemcial and oxidative. Mechanical methods also include (ultra) sonication and high shear mixing.
2. Bottom Up: Graphene produced from gases by Chemical Vapour Deposition (CVD).
There is also the approach that involves the unzipping of carbon nanotubes (CNTs) to obtain graphene nanoribbons / nano-strips.
Graphene production - High Pressure Homogenizers - Liquid-phase exfoliation (LPE)
Our industry-leading high pressure technology provides one of the most promising methods to help meet challenges listed below for Graphene exfoliation.
Production scale Homogenizer system
Challenges of Graphene production
Scalability of production to high levels without negative impact on its properties.
Low graphene yields.
The quality of graphene produced and so its electrical conductivity and strength.
Some methods produce hazardous waste and poisonous gases.
One of its most promising features of our high pressure Homogenizers is their ability to scale-up to higher production levels and to do so with repeatable results for improved product consistency.
One example would be the production of large volumes of conductive Graphene ink from a flake graphite solution which undergoes high energy / high-shear in our homogenizer processing chamber. The end result (after several processing cycles) is a highly concentrated graphene suspension.
Increasing Graphene yields.
For example, when processing Flake Graphite the yields of Graphene (when not using our technology) are typically small. Obviously this is inefficient and so increases production costs and time.
The high shear process of our Homogenizers can increase Graphene yields and this percentage can be increased, incrementally, in each additional cycle through the Homogenizer .
Improving Graphene quality.
The quality / purity of Graphene produced can be determined by multiple factors, not just the method of Graphite exfoliation used.
Pristine Graphene can be achieved when using a class-leading Homogenizer, like ours, when using high-quality Flake Graphite as the raw material. HPH can be used to ensure mild exfoliation conditions that can help to decrease the formation of defects.
Other factors that can have affect on Graphene purity include the introduction of various solvents or surfactant/water solutions.
Another benefits of using HPH is that by adjusting the pressure and processing time the thickness distribution and Graphene 'sheet' area distribution can be controlled.
Lowering Graphene Production costs.
HPH can utilize Flake Graphite - a cheap and abundant source - as the raw material for Graphene production.
HPH has the ability for scaleable, continuous processing to maximise Graphene production, yields and with repeatable results.
HPH does not (normally) require the use expensive substrates during processing.
As shown in the diagram below, the solution is recycled from the outlet reservoir back in to the inlet reservoir (for another cycle) and this can increases yield and lower production costs.
During each cycle the graphite flakes, which can move within the liquid, can be exfoliated repeatedly at different positions inside the homogenizer chamber whilst under very high pressure. Tests show that Graphene particles produced are about 1 to 2 micron in lateral size with a uniform end product.
So our High Pressure Homogenzers are proving to be a cost-effective, and efficient, Graphene exfoliation method.
Production scale system
Laboratory Homogenizer for R&D