New method improves industrial viability of graphene production

The new technique, developed by a team led by researchers at the National University of Singapore (NUS), is claimed to address the long-standing challenge of efficiently processing graphene on a large-scale. It also paves the way for sustainable synthesis of the material.

The conventional method of graphene production utilises sound energy or shearing forces to exfoliate graphene layers from graphite, and then dispersing the layers in large amounts of organic solvent.

As insufficient solvent causes the graphene layers to reattach themselves back into graphite, yielding one kilogram of graphene currently requires at least one tonne of organic solvent, making the method costly and environmentally unfriendly.

The NUS-led development is claimed to use up to 50 times less solvent. This is achieved by exfoliating pre-treated graphite under a highly alkaline condition to trigger flocculation, a process in which the graphene layers continuously cluster together to form graphene slurry without having to increase the volume of solvent. The method also introduces electrostatic repulsive forces between the graphene layers and prevents them from reattaching themselves.