▎ 摘　　要

NOVELTY - A graphene dispersion liquid is obtained by dispersing graphene in a solvent comprising 50 %mass or more N-methylpyrrolidone. The weight absorptivity coefficient of a dilution liquid of graphene dispersion liquid having graphene weight fraction adjusted to 0.000013 using N-methylpyrrolidone at a wavelength of 270 nm is 25000-200000 cm-1, which is calculated using a specific relation (I). USE - Graphene dispersion liquid is used for manufacturing active material composite particles for manufacturing paste (all claimed) for forming electrode of battery e.g. lithium ion battery. Can also be used for energy storage material, electronic device, and composite material. ADVANTAGE - The graphene dispersion liquid has excellent dispersibility of graphene, and adsorption performance of graphene with respect to surface of inorganic particles, and suppressed aggregation of graphene, and provides electrode with excellent electroconductivity and ionic conductivity for long period of time, by simple process. DETAILED DESCRIPTION - A graphene dispersion liquid is obtained by dispersing graphene in a solvent comprising 50 %mass or more N-methylpyrrolidone. The weight absorptivity coefficient of a dilution liquid of graphene dispersion liquid having graphene weight fraction adjusted to 0.000013 using N-methylpyrrolidone at a wavelength of 270 nm is 25000-200000 cm-1, which is calculated using the relation: weight absorptivity coefficient (cm-1)=absorbance/(0.000013x (optical path length (cm) of cell)) (I). INDEPENDENT CLAIMS are included for the following: (1) manufacture of graphene electrode active material composite particles, which involves mixing the graphene dispersion liquid and electrode active material particles, and drying; (2) manufacture of electrode paste, which involves mixing an electrode active material, a binder, and the graphene dispersion liquid; and (3) manufacture of graphene dispersion liquid, which involves reducing the graphene oxide dispersed in a dispersion medium containing water, mixing an intermediate material dispersion liquid obtained after the reduction process and the solvent, stirring the intermediate material dispersion liquid at shear rate of 5000-50000/second, removing a portion of moisture content from the intermediate material dispersion liquid by N-methylpyrrolidone-containing solvent addition and suction filtration process, or distillation process.