NOVELTY - A graphene sheet composition comprises 30-100% graphene as main component, and is obtained by treating graphite in a supercritical fluid.    USE - Graphene sheet composition is used for negative electrode active material for lithium ion secondary battery, conductive support agent for electrode for battery, and resin composite material (all claimed). Uses include but are not limited to electromagnetic wave shield, conductive connection material and electronic components e.g. personal computer, personal digital assistance, mobile telephone and liquid crystal television.    ADVANTAGE - The graphene sheet composition provides negative electrode active material and conductive agent capable of providing battery with excellent discharge characteristics and charge/discharge characteristics, and resin composite material with excellent electroconductivity, and is manufactured in a short time.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) negative electrode active material, which includes the graphene sheet composition;    (2) lithium ion secondary battery, which consists of the negative electrode active material;    (3) conductive support agent, which includes the graphene sheet composition;    (4) electrode, which has the conductive support agent;    (5) resin composite material, which consists of the graphene sheet composition, and synthetic resin;    (6) manufacture of graphene sheet composition, which involves supplying (S110) solvent containing graphite to supercritical treatment plant, converting (S120) the solvent into supercritical state, returning (S130) solvent from supercritical state to non-supercritical state, and performing continuous flow of the solvent, and repeating (S140) the above processes continuously and/or discontinuous for multiple times; and    (7) manufacture apparatus of graphene sheet composition, which consists of unit to supply solvent containing graphite to supercritical treatment plant, unit for the conversion of fluid into supercritical state, unit to return solvent from supercritical state to non-supercritical state, and unit for performing the flow of solvent by continuous flow system.    DESCRIPTION OF DRAWING(S) - The drawing shows a flowchart explaining the manufacture of the graphene sheet composition. (Drawing includes non-English language text)    Supply process (S110)    Conversion process (S120)    Returning process (S130)    Repeating process (S140)