The purification of mesoscopic graphene flakes via eddy current separation.

Abstract

The exceptional properties of graphene are highly sensitive to impurities, which restrict its applications. Nearly all large-scale production methods fail to sufficiently control the impurities introduced during manufacturing. Given the significant differences in electrical conductivity between graphene and non-graphene impurities, we explored the application of eddy current separation for the purification process of graphene. Through numerical simulations and parametric study, our research investigates the eddy current forces, torques, and motion dynamics experienced by graphene flakes of different layers in an alternating magnetic field. The findings demonstrate that eddy current forces can overcome liquid-phase resistance, enabling controlled directional movement of graphene flakes. At a magnetic field frequency of 45 kHz, graphene flakes with fewer layers show enhanced settling velocities and quicker response times, suggesting a potential for statistically significant separation of graphene from impurities under the influence of the alternating magnetic field. This initial study supports the feasibility of integrating eddy current separation technology into the graphene purification process, providing valuable insights for future research in this field.