One of the major obstacles graphene researchers are working to overcome in the mass commercialization of the material is the high cost of production. But synthesized graphene suitable for as much as 90% of its applications can be synthesized using graphite powder, water, detergents, and solvents in a method called liquid-phase exfoliation.
The process results in a scalable form of multi-layer graphene at a relatively low cost. It involves dispersing graphite flakes into a solution made of intercalating agents which position themselves between layers of the material, according to Azo Nano. The key is using the correct surfactant, which serves as a wall that surrounds the graphene surfaces and prevents the graphene flakes from reverting to graphite.
Graphite is submerged in a solvent and exposed to ultrasonic vibrations which exfoliate the graphene. The solution is then filtered multiple times to organize the graphene by size and number of layers. At this point the graphene is ready to use in an organic solvent. With further processing, it can become functional graphene ink.
Liquid-phase exfoliation of graphene is a favored method because of its scalability, thanks to graphite’s ready availability, as well as its relatively low production cost. The resulting graphene is high-quality, and can be scaled. Waste is also reduced because any graphite that fails to convert to graphene can be reused in subsequent graphene production attempts.