▎ 摘　　要

NOVELTY - A potassium ion modified graphene composite material is prepared by coating graphene oxide dispersion on single surface of hydrophobic film, drying and stripping hydrophobic film to obtain graphene oxide film, thermally reducing graphene oxide film to obtain graphene film, putting graphene film in self-sealing bag, adding potassium-containing inorganic salt solution into self-sealing bag, exhausting gas in self-sealing bag, soaking graphene film in potassium-containing inorganic salt solution, and drying. USE - The method is used for preparing potassium ion modified graphene composite material. ADVANTAGE - The material has simple operation, low cost and excellent potassium storage performance, and displays high capacity, good rate charging and discharging performance and cycle stability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for potassium ion battery comprising potassium ion modified graphene composite material as cathode.