The liquid-phase preparation of graphene by shear exfoliation with graphite oxide as a dispersant

In this paper, we reported an environmentally friendly and scalable approach to prepare graphene from industrial isostatic graphite (IIG) using a high speed homogeneous disperser and graphite oxide. We have successfully prepared a stable graphene dispersion (GOG) containing graphene oxide. In this process, the dispersant eventually was converted to product by an additional process. The lateral size of graphene ranged from 5 to 10 mu m and 70% of the graphene was less than 5 layers. By electrochemical analysis, the specific capacitance was as high as 121F/g and the equivalent resistance of graphene was about 2.8 Omega. After 3000 times cycles at a scan rate of 50 mV/s(-1), the capacitance retention rate was 95.8%, indicating that the prepared graphene sheets have good capacitance stability. This method is simple, inexpensive and easy to scale up.