Green solvents for the liquid phase exfoliation production of graphene. The promising case of Cyrene

The liquid phase exfoliation (LPE) of graphite has allowed to produce graphene materials on a large scale and at a reasonable cost. By this method, stable dispersions, inks and liquid suspensions containing atomic-thick graphene flakes with tailored concentrations can be produced, opening up applications in a wide range of cutting-edge technologies such as functional coatings, printed and flexible electronics, and composites. However, currently established LPE techniques raise several health and environmental risks, since unsafe and toxic solvents (such as NMP, DMF, and DMSO) are often regarded as the most effective liquid media for the process. Therefore, it appears necessary to unlock eco-friendly and sustainable methods for the production of graphene at an industrial scale. This review focuses on the latest developments in terms of green solvents for LPE production of graphene. We highlight the use of a new green solvent, Cyrene, and its performance when compared to conventional solvents.