One-step room-temperature exfoliation of graphite to 100% few-layer graphene with high quality and large size
Abstract
Large scale application of graphene is still facing a great challenge due to the lack of cost-effective methods for its production. Herein, we report a simple and cost-effective method for scalable production of few-layer graphene (FLG) with high quality and large size in only one step at room temperature. In this method, a novel binary-component system, which is composed of sodium percarbonate (SPC) and concentrated H2SO4, has been developed for the chemical exfoliation of graphite, where sodium percarbonate is used to exfoliate graphite for the first time, furthermore, the amount of the concentrated H2SO4 used as an intercalating agent is reduced dramatically by 83–85% in comparison to those in the other chemical exfoliation methods. It is found that SPC plays a key role in the exfoliation of graphite. Considering the analysis results, a possible mechanism for the exfoliation of graphite to FLG is proposed. The exfoliated graphene sheets exhibit a few-layer feature (average layer number <5 layers), and possess large areal sizes (the maximum areal size can be up to 538 μm2, and the average sheet area is 276.8 μm2) and few structural defects (the oxygen content is only 1.65%), thereby exhibiting an outstanding electrical conductivity of 1.90 × 105 S m−1.