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.