▎ 摘　　要

NOVELTY - Graphene compound comprises optionally substituted chain group and a graphene layer. The chain group comprises at least one ester or carboxy group, where the chain group preferably comprises a silicon atom. The chain group is bonded to the graphene layer through the silicon atom. USE - The graphene compound is useful for manufacturing a power storage device (claimed) e.g. a lithium-ion storage battery, a semiconductor device, a display device, a light-emitting device, a power storage device and a memory device. ADVANTAGE - The graphene compound: provides the power storage device that has high flexibility and can be used in a wide temperature range because of its high heat resistance e.g. in a car for a long time; exhibits a function of conducting metal ions e.g. lithium, sodium, magnesium and calcium and thus can be used for a solid electrolyte of a lithium-ion storage battery; utilizes the silicon compound that has low electron conductivity and high lithium ion conductivity and thus is favorably used for a solid electrolyte or a separator of a lithium-ion storage battery; and has a long functional group that prevents a short circuit (an internal short circuit) between a positive electrode and a negative electrode, hence safe. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) a power storage device comprising the graphene compound (105), an exterior body (109), a positive electrode current collector (100) and a negative electrode current collector (102); and (2) forming a graphene compound, comprising stirring graphene oxide and a Lewis base to form a first mixed solution, mixing a silicon compound that comprises at least one ester or carboxy group into the first mixed solution and stirring the mixed solution to form a second mixed solution, and filtering the second mixed solution and collecting an obtained residue, where the residue comprises a graphene compound. DESCRIPTION OF DRAWING(S) - The diagram shows a schematic cross-sectional view of a lithium-ion storage battery. Positive electrode current collector (100) Negative electrode current collector (102) Graphene compound (105) Exterior body (109) Lithium-ion storage battery (110)