High yield, solid exfoliation and liquid dispersion of graphite driven by a donor-acceptor interaction

Abstract

Graphene derived from readily available graphite is viewed as the most effective route for large-scale production, due to the low cost of the raw material. However, the difficulty in achieving complete exfoliation, as well as the intrinsic insolubility of graphite, remains a key challenge. Herein, we describe a single-step approach to effectively disrupt and cleave the network of π–π interactions, induce the exfoliation of graphite and disperse the resulting exfoliated material in organic solvents, all driven by electron rich (graphene) donor-acceptor interactions. This is achieved through the addition of specially synthesised non-polar, branched, electron-deficient aromatic acceptor molecules. Minimal energy input through mild manual grinding of graphite with the tailored acceptor induces donor-acceptor interactions that preferentially affect the π−π system in graphite resulting in solid phase exfoliation. Graphite exfoliation and dispersion formation is further improved after mild bath sonication (30 min) of the acceptor-graphite composite in a solvent leading to 1250% increment in yield in NMP solvent for instance. The use of electron acceptors allows high concentration dispersions, not only in high boiling point solvents, whose surface energy generally matches that of graphene but also in a low boiling point solvent with mediocre properties.