▎ 摘　　要

NOVELTY - A graphene-based composite comprises a graphene layer (l1), a graphene layer (l2) spaced apart from layer (l1), and a coupling agent provided between layers (l1) and (l2). The coupling agent is a substituted polycyclic compound (I). USE - Graphene-based composite is used in hydrogen storage medium (claimed). ADVANTAGE - The lightweight graphene-based composite has high specific surface area and high hydrogen storage capacity, and can be mass produced by environmentally-friendly process with structural controllability. DETAILED DESCRIPTION - A graphene-based composite comprises a graphene layer (l1), a graphene layer (l2) spaced apart from layer (l1), and a coupling agent provided between layers (l1) and (l2). The coupling agent is a substituted polycyclic compound of formula (I). R1=-H, -OH or 1-3C alcohol; R2=-OH, -NH2 or -NHCH3; R3=-H or -OH; wavy line=1-10C linear or branched alkyl;and n=integer. An INDEPENDENT CLAIM is included for manufacture of graphene-based composite, which involves preparing graphene oxide from graphite, dispersing resultant in a solvent, adding compound (I) to the mixed solution, dispersing, and adjusting pH of resultant mixture using a buffer solution.