▎ 摘　　要

NOVELTY - Preparing a graphene material, comprises: (a) dispersing graphite powder in a solvent to form a dispersion; (b) shearing the dispersion with a high shear rate between 106 to 109 per second to exfoliate the graphite into a graphene material; (c) heating the sheared dispersion of the step (b) to reach supercritical conditions of the solvent and maintain supercritical conditions for a period of time; and (d) drying the graphene material by removing the solvent from the dispersion while the dispersion is held above the critical temperature of the solvent, to preserve the exfoliated condition of the graphene material. USE - The method is useful for preparing a graphene material. ADVANTAGE - The method: is efficient and effective method; utilizes inexpensive starting graphite materials with no harsh chemicals or high temperatures involved; provides high-quality graphene materials; and is scalable up to the industrial level and cost-efficient. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) graphene material in a form of powder having less than 20% unexfoliated graphite as flakes greater than 25 nm in thickness, as determined by statistical analysis via atomic force microscopy; and (2) graphene material in a form of powder, having a mean flake thickness of 8-12 nm, as determined by statistical analysis via atomic force microscopy.