Production of Graphene-Based Supercapacitor Electrode from Coke or Coal Using Direct Ultrasonication

A process for producing a graphene-based supercapacitor electrode from a supply of coke or coal powder containing therein domains of hexagonal carbon atoms and/or hexagonal carbon atomic interlayers with an interlayer spacing, said process comprising:

• (a) dispersing particles of said coke or coal powder in a liquid medium containing therein an optional surfactant or dispersing agent to produce a suspension or slurry, wherein said coke or coal powder is selected from the group consisting of petroleum coke, coal-derived coke, meso-phase coke, synthetic coke, leonardite, anthracite, lignite coal, bituminous coal, natural coal mineral powder, and a combination thereof;
• (b) exposing said suspension or slurry to ultrasonication at an energy level for a sufficient length of time to produce a graphene suspension containing isolated graphene sheets dispersed in said liquid medium;
• and
• (c) shaping and drying said graphene suspension to form said supercapacitor electrode that is porous and has a specific surface area greater than 200 m2/g.