▎ 摘　　要

NOVELTY - Graphene oxide is grafted with 4-aminophenoxyphthalonitrile, to obtain cyano-functionalized graphene. The cyano-functionalized graphene is subjected to continuous ultrasonic precipitation and high-speed ball milling to obtain uniform dispersion of crosslinked poly(aryl ether nitrile)/cyano-functionalized graphene ultrafine powder. The uniform dispersion of crosslinked poly(aryl ether nitrile)/cyano-functionalized graphene ultrafine powder is melt-pressed to form high-strength, high-temperature-resistant polymer-based dielectric film with desired thickness and controlled size. USE - Preparation of high-strength, high-temperature-resistant polymer-based dielectric film used for dielectric energy storage system (claimed). ADVANTAGE - The method enables preparation of polymer-based dielectric film with glass transition temperature of more than 360 degrees C, tensile strength of more than 450 MPa and modulus of more than 4.5 GPa, excellent flexibility, dielectric constant of 11-28.5, and dielectric loss of 0.02-0.045.