▎ 摘　　要

NOVELTY - Graphene oxide prepared using graphite as raw material, potassium permanganate and hydrogen peroxide, and dopamine hydrochloride are mixed, aqueous ammonia is dripped, and polymerization of dopamine is carried out. A reducing agent is added to the obtained product, and dispersed in organic solvent, to obtain polydopamine-modified graphene. Polyvinylidene fluoride is dissolved in organic solvent, polydopamine-modified graphene is added, stirred, dried, and hot-press molded, to obtain polyvinylidene fluoride/polydopamine-coated graphene nano composite material. USE - Preparation of polyvinylidene fluoride/polydopamine-coated graphene nano composite material used as dielectric material for energy storage devices e.g. capacitor. ADVANTAGE - The method enables simple and easy preparation of polyvinylidene fluoride/polydopamine-coated graphene nano composite material having excellent flexibility and workability, and high dielectric constant. DETAILED DESCRIPTION - Graphite as raw material is added to potassium permanganate as oxidizing agent, and hydrogen peroxide as pro-oxidizing agent, reacted in 98% concentrated sulfuric acid at 0-98 degrees C for 6-24 hours, washed using deionized water, and dispersed in water, to obtain graphene oxide. 0.05-0.2 Wt.% graphene oxide and 0.05-0.4 wt.% dopamine hydrochloride as modifying agent are mixed, aqueous ammonia or pH buffering solution is dripped, pH value is adjusted to alkaline, stirred, polymerization of dopamine is carried out, washed, and resultant polydopamine-coated graphene oxide is dispersed in solvent. A reducing agent is added to the obtained product, graphene oxide is reduced into graphene, resultant product is washed, and dispersed in organic solvent by ultrasonic treatment, to obtain polydopamine-modified graphene. Polyvinylidene fluoride is dissolved in organic solvent, polydopamine-modified graphene is added, stirred, the resultant mixture is poured into a petri dish system, dried, and hot-press-molded, to obtain polyvinylidene fluoride/polydopamine-coated graphene nano composite material.