▎ 摘　　要

NOVELTY - Preparation of graphene composite material involves adding and mixing graphene material and a modification solution comprising a compound having catechol group and a solvent (S1). USE - Preparation of graphene composite material (claimed) used in communication systems, solar panels, battery materials, touch panel, biomedical engineering, environmental engineering and electronic devices. ADVANTAGE - The method produces graphene composite material having excellent dispersibility in water and graphene composite material thin film having excellent electroconductivity. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for graphene composite material, which comprises 70-99.9 wt.% graphene material and 0.1-30 wt.% compound coated on a surface of graphene material.