▎ 摘　　要

NOVELTY - The method involves dispersing graphene oxide and water-soluble lignin evenly in a solvent and evenly coating as an ultra-thin composite film on a substrate and drying, and the hydrophilic angle theta of the substrate is more than 65degrees - 90degrees. The chemical steam is reduced. The substrate is inserted into the water at a certain angle, and the ultra-thin composite film is peeled off from the substrate. The water is replaced with a volatile solvent. The ultra-thin composite membrane is extracted by using a rough porous substrate, and the membrane is automatically detached after drying to obtain an independently supported ultra-thin graphene composite membrane. The ultra-thin film obtained is sintered at 2800degrees C to repair defects, and finally a high-crystalline ultra-thin graphite film is obtained. USE - Preparation method of independent self-supporting ultra-thin graphite film. ADVANTAGE - The method solves the problem that the ultra-thin graphite film is hard to be supported independently. The oxidation graphene or water-soluble lignin is soaked in the water solvent, the swelling effect occurs, and the physical cross-linking effect of reducing oxidation graphene prevents over swelling, maintains the integrity of the film. The hydrogen bonding between graphene oxide, water-soluble lignin and water is stronger than the interfacial binding energy between the composite film and the substrate, thereby reducing the interfacial energy between the substrate and the film and promoting the local separation of the film from the substrate. The method creatively uses the solvent surface tension and water shearing action, to solve the problem of peeling after carbonization. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of mechanical analysis of the peeling process of preparation method of an independent self-supporting ultra-thin graphite film.