▎ 摘　　要

NOVELTY - Composite film material is prepared by binding vanadium dioxide (B) nanobelts and graphene nanosheets. The width of vanadium dioxide (B) nanobelts in composite film material is 100 nm and length is 3-5 mu m. USE - Composite film material used as positive and negative electrode material in all-solid-state supercapacitor (claimed). ADVANTAGE - The composite film material is assembled into an all-solid-state supercapacitor with high energy density of 9 Wh/kg and power density of 250 W/kg, and has excellent cycle stability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of composite film material, which involves using vanadium salt, reducing acid, graphene oxide, and reducing agent.