| abstract |
Provided is a process for producing a graphene-based supercapacitor electrode from a supply of coke or coal powder, comprising: (a) exposing this powder to a supercritical fluid for a period of time in a pressure vessel to enable penetration of the supercritical fluid into internal structure of the coke or coal; wherein the powder is selected from petroleum coke, coal-derived coke, meso-phase coke, synthetic coke, leonardite, anthracite, lignite coal, bituminous coal, or natural coal mineral powder, or a combination thereof; (b) rapidly depressurizing the supercritical fluid at a fluid release rate sufficient for effecting exfoliation and separation of the coke or coal powder to produce isolated graphene sheets, which are dispersed in a liquid medium to produce a graphene suspension; and (c) shaping and drying the graphene suspension to form the supercapacitor electrode having a specific surface area greater than 200 m2/g. |