Low-temperature, rapid preparation of functionalized graphene platelets

Abstract

Graphene holds promise for the development of advanced materials from battery electrodes to sensors to structural composites. However, the current preparation methods of graphene rely on long-time oxidation where particularly hazardous materials are involved. We herein report a simple, cost-effective approach to scalable preparation of solution-processible yet high-structural integrity graphene, by heating a mixture of graphite, sulfuric acid and potassium persulfate at 70 °C for 7 min. The obtained graphene platelets have average thickness of 3.88 ± 0.80 nm and a lateral dimension below 2 μm, with a Raman ID/IG of 0.06. As measured by a 4-point probe method, a graphene platelet film exhibits surface resistance of 0.70 ± 0.10 Ω/sq, corresponding to electrical conductivity of 1618.12 ± 261.56 S/cm. The as-prepared platelets have carboxyl, epoxide and hydroxyl groups on the surface, and thus the functionalized graphene platelets should be compatible with many polymers. The platelets can suspend in ethanol at 1 mg/ml for up to 3 h.