▎ 摘　　要

NOVELTY - Preparing graphene dried powder, involves: (a) sonication of graphite in a mixture of water and a volatile organic solvent; (b) centrifugation of the product obtained in step (a); (c) filtration of the product obtained in step (b) to remove graphene flakes having lateral dimensions larger than 1x 1 mu m; and (d) addition of a precipitating agent to the solution obtained in step (c) to precipitate the graphene flakes, and filtration to collect graphene dried powder, or alternatively, (d1) solvent evaporation to obtain graphene dried powder. USE - The process is useful for preparing graphene dried powder, which is useful for preparing a graphene flake composition, which is useful in an ink composition, for coating surfaces, preferably silicon dioxide, gold, acetate paper, or glass surfaces by ink-jet printing, spray deposition, centrifugation techniques, spin coating, drop casting, dip coating, electrospray and Meyer rod method (all claimed), and for coating surfaces such as metal surfaces (including silver and copper), semiconductors (including monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, copper indium selenide, and copper indium sulfide), polymer surfaces (including polyethylene terephthalate, polycarbonate, styrene, and vinyl), paper surfaces (including cardstock, chipboard, metal foil, vellum, cotton fiber, and cover paper) and glass surfaces (including silica and silicates). ADVANTAGE - The process provides graphene dried powder with high yield. The graphene dried powder provides graphene flake composition showing a dispersion of uniform size flakes of graphene in organic volatile solvents. The graphene flake composition is stable, homogeneously coats surfaces of different materials via printing techniques, and has good wetting or drying property. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) graphene dried powder obtained by the process; (2) preparing a graphene flake composition comprising graphene flakes having lateral dimensions of less than 1x 1 mu m and a matrix, comprising redispersing the graphene dried powder in a matrix; (3) the graphene flake composition comprising graphene flakes having lateral dimensions of less than 1x 1 mu m dispersed in a matrix; and (4) an ink composition comprising the graphene flake composition, optionally including dyes, resins, lubricants, solubilizers or surfactants.