▎ 摘　　要

NOVELTY - Preparing carbon-coated tin selenide composite glue-linked three-dimensional graphene comprises e.g. mixing graphite powder, potassium permanganate, sulfuric acid, carrying out hydrothermal reaction to obtain mixture A, cooling, mixing with deionized water to obtain mixed solution, adding hydrogen peroxide in mixed solution until mixed solution does not bubble, allowing to stand and layering, adjusting pH value to obtain graphene oxide slurry B, freezing and drying; mixing graphene oxide C and deionized water, and dispersing; carrying out hydro-thermal reaction, freezing and drying to obtain cylindrical three-dimensional graphene F, mixing selenium powder and reducing solvent to obtain mixed solution H, carrying out hydrothermal reaction to obtain reaction product, separating and collecting the reaction product to obtain powder and drying powder to obtain product X, mixing, performing uniform phase reaction to obtain the black powder Z, and calcining. USE - The carbon-coated tin selenide composite gel-linked three-dimensional graphene is used as a cathode material of potassium ion battery. ADVANTAGE - The graphene exhibits excellent electrochemical performance, and has wide application prospect. DESCRIPTION OF DRAWING(S) - The drawing shows an XRD pattern of carbon-coated tin selenide composite glue-linked three-dimensional graphene prepared by the embodiment 1 of the present invention.